I have a certain piece of code that I'm trying to use with PHP Version 5.2.14 . Is it incompatible?? I run the following,
jailshell-3.2$ php -l /XYZ/functions.php
And it gives:
Parse error: syntax error, unexpected T_FUNCTION, expecting ')' in /XYZ/functions.php on line 2115
Errors parsing /XYZ/functions.php
The code is:
2114 $range = array_map(
2115 function (DatePeriod $p) use ($vt2) {
2116 $res = array();
Why does the following code output 128?
print 4 << 5;
?>
Answer
Because it's a bitwise operator. I think it means 4 multiplied to 2^5 because that operator means
Shift the bits of $a $b steps to the left (each step means "multiply
by two")
so it's five steps. It's 4 * 2 * 2 * 2 * 2 * 2 (But I'm guessing here; everything happens at bit level).
How can I generate an n-character pseudo random string containing only A-Z, 0-9 like SecureRandom.base64 without "+", "/", and "="? For example:
(0..n).map {(('1'..'9').to_a + ('A'..'Z').to_a)[rand(36)]}.join
Answer
Array.new(n){[*"A".."Z", *"0".."9"].sample}.join
I need to do a pretty simple task,but since im not versed in R I don't know exactly how to. I have to create a vector of 100 numbers with random values from 0 to 1 with 2 DECIMAL numbers. I've tried this:
x2 <- runif(100, 0.0, 1.0)
and it works great, but the numbers have 8 decimal numbers and I need them with only 2.
How can I format a JavaScript date object to print as 10-Aug-2010?
Answer
Attention: There are better answers below. This answer was written in 2010 and newer and better solutions have arrived since. The OP should accept another answer.
function formatDate(date) {
var monthNames = [
"January", "February", "March",
"April", "May", "June", "July",
"August", "September", "October",
"November", "December"
];
var day = date.getDate();
var monthIndex = date.getMonth();
var year = date.getFullYear();
return day + ' ' + monthNames[monthIndex] + ' ' + year;
}
console.log(formatDate(new Date())); // show current date-time in consoleYou can edit the array monthNames to use Jan, Feb, Mar, etc..
I have been trying to work out a solution to this issue, and have come across many similar posts online,.. but none with solutions that worked for my particular instance.
I'm using jQuery it 'inserAfter' within a group of elements. I can add the groups easily,.. but, I also have a remove() function called when a delete link is clicked,.. but nothing happens to the newly added elements, even though I can delete the other groups without problems.
I'm using jQuery's on() for the click function.. but, that still doesn't work on the dynamically added elements.
To reproduce the issue, go to the jsfiddle link below,
Click the ADD GROUP button and see a yellow group added to the DOM.
Now, hover over the yellow group to show the delete button.
Click the delete button and, tada... nothin'
Here is an example:
http://jsfiddle.net/revive/5MFRm/
jQuery(function($) {
$( "#tabs" ).tabs();
$("#group0").hide();
$('.group-content').hide(); // Hide all group-content elements
function clonePanel() {
var panel=$("#tabs #group0").clone(false),
lastpanel = $("#tabs .group").last().index(),
newid = 'group'+(lastpanel+1);
panel.attr('id',newid).addClass('newpanel');
panel.insertAfter($("#tabs .group").last()).show();
}
$(".add-group").on('click',function(){
clonePanel();
});
$(".delete-group").on('click',function(){
$(this).closest('.group').fadeOut('slow', function(){$(this).closest('.group').remove(); });
// alert('done');
});
$('#tabs').on('click', '.group-title-toggle',function(){ // Add class "hover" on dt when hover
$(this).closest('.group-title').toggleClass('active').next().slideToggle(); // Toggle dd when the respective dt is clicked
});
});
Answer
That is what you are looking for: In jQuery, how to attach events to dynamic html elements?.
And here is your code working properly.
http://jsfiddle.net/5MFRm/2/
Instead of $('.add-group').on('click', function() {})
use this notation
$('body').on('click', '.add-group', function() {})
Television show of the 90s involving solving the mystery of the death of a high school girl of the Pacific Northwest, Laura Palmer, and the supernatural events surrounding the principal suspects, their friends, and enemies.
A friend of mine and I are currently discussing what is a closure in JS and what isn't. We just want to make sure we really understand it correctly.
Let's take this example. We have a counting loop and want to print the counter variable on the console delayed. Therefore we use setTimeout and closures to capture the value of the counter variable to make sure that it will not print N times the value N.
The wrong solution without closures or anything near to closures would be:
for(var i = 0; i < 10; i++) {
setTimeout(function() {
console.log(i);
}, 1000);
}
which will of course print 10 times the value of i after the loop, namely 10.
So his attempt was:
for(var i = 0; i < 10; i++) {
(function(){
var i2 = i;
setTimeout(function(){
console.log(i2);
}, 1000)
})();
}
printing 0 to 9 as expected.
I told him that he isn't using a closure to capture i, but he insists that he is. I proved that he doesn't use closures by putting the for loop body within another setTimeout (passing his anonymous function to setTimeout), printing 10 times 10 again. The same applies if I store his function in a var and execute it after the loop, also printing 10 times 10. So my argument is that he doesn't really capture the value of i, making his version not a closure.
My attempt was:
for(var i = 0; i < 10; i++) {
setTimeout((function(i2){
return function() {
console.log(i2);
}
})(i), 1000);
}
So I capture i (named i2 within the closure), but now I return another function and pass this around. In my case, the function passed to setTimeout really captures i.
Now who is using closures and who isn't?
Note that both solutions print 0 to 9 on the console delayed, so they solve the original problem, but we want to understand which of those two solutions uses closures to accomplish this.
Answer
Editor's Note: All functions in JavaScript are closures as explained in this post. However we are only interested in identifying a subset of these functions which are interesting from a theoretical point of view. Henceforth any reference to the word closure will refer to this subset of functions unless otherwise stated.
A simple explanation for closures:
Now let's use this to figure out who uses closures and who doesn't (for the sake of explanation I have named the functions):
Case 1: Your Friend's Program
for (var i = 0; i < 10; i++) {
(function f() {
var i2 = i;
setTimeout(function g() {
console.log(i2);
}, 1000);
})();
}
In the above program there are two functions: f and g. Let's see if they are closures:
For f:
i2 is a local variable.i is a free variable.setTimeout is a free variable.g is a local variable.console is a free variable.i is bound to the global scope.setTimeout is bound to the global scope.console is bound to the global scope.i is not closed over by f.setTimeout is not closed over by f.console is not closed over by f.Thus the function f is not a closure.
For g:
console is a free variable.i2 is a free variable.console is bound to the global scope.i2 is bound to the scope of f.setTimeout.console is not closed over by g.i2 is closed over by g.Thus the function g is a closure for the free variable i2 (which is an upvalue for g) when it's referenced from within setTimeout.
Bad for you: Your friend is using a closure. The inner function is a closure.
Case 2: Your Program
for (var i = 0; i < 10; i++) {
setTimeout((function f(i2) {
return function g() {
console.log(i2);
};
})(i), 1000);
}
In the above program there are two functions: f and g. Let's see if they are closures:
For f:
i2 is a local variable.g is a local variable.console is a free variable.console is bound to the global scope.console is not closed over by f.Thus the function f is not a closure.
For g:
console is a free variable.i2 is a free variable.console is bound to the global scope.i2 is bound to the scope of f.setTimeout.console is not closed over by g.i2 is closed over by g.Thus the function g is a closure for the free variable i2 (which is an upvalue for g) when it's referenced from within setTimeout.
Good for you: You are using a closure. The inner function is a closure.
So both you and your friend are using closures. Stop arguing. I hope I cleared the concept of closures and how to identify them for the both of you.
Edit: A simple explanation as to why are all functions closures (credits @Peter):
First let's consider the following program (it's the control):
lexicalScope();
function lexicalScope() {
var message = "This is the control. You should be able to see this message being alerted.";
regularFunction();
function regularFunction() {
alert(eval("message"));
}
}lexicalScope and regularFunction aren't closures from the above definition.message to be alerted because regularFunction is not a closure (i.e. it has access to all the variables in its parent scope - including message).message is indeed alerted.Next let's consider the following program (it's the alternative):
var closureFunction = lexicalScope();
closureFunction();
function lexicalScope() {
var message = "This is the alternative. If you see this message being alerted then in means that every function in JavaScript is a closure.";
return function closureFunction() {
alert(eval("message"));
};
}closureFunction is a closure from the above definition.message not to be alerted because closureFunction is a closure (i.e. it only has access to all its non-local variables at the time the function is created (see this answer) - this does not include message).message is actually being alerted.What do we infer from this?
I'm looking for algorithms that can combine images based on a quality factor. For example, you have 50-100 photographies of the same scene, but some areas had bad quality in some image because artefacts or whatever.
Now for each pixel I select the best one with a quality factor based in darkness but for sure we have a lot off possible combinations and a lot a quality measures pixel/patch/image-based.
I'm trying to research about this topic but I don't found how to describe it properly, do you know some algorithms or at least which is de name of this "problem"?
Update: Note some desired pixels or pixel areas only appears in a few cases, e.g. in 10 of 100 images. It causes we can't use simple averaging or similar methods.
So I got this JSON Object. And I would like to iterate throug all the Objects in nodes but the Objects the nodes Object is not formatet as an Array with []
I can access one after the other, if I know the name for example:
var X = Trend.L13
var node = X.nodes["AGENT.OBJECTS.House.SKL04_SK2.L13.Frost.AL01"]
But how do I iterate them?
var Trend = {
L13: {
dataArchive: "datavalues",
nodes: {
"AGENT.OBJECTS.House.SKL04_SK2.L13.Frost.AL01": {
visible: true,
axis: "left",
style: "Line",
color: "#66AF31",
linewidth: 1,
nonstop: true,
stairs: true,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.Frost.AL01",
text: "Frost"
},
"AGENT.OBJECTS.House.SKL04_SK2.L13.TempZul.MT01": {
visible: true,
axis: "right",
style: "Line",
color: "#8701AF",
linewidth: 1,
nonstop: true,
stairs: false,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.TempZul.MT01",
text: "Temp ZUL"
},
"AGENT.OBJECTS.House.SKL04_SK2.L13.PuWrg.SS01": {
visible: true,
axis: "left",
style: "Line",
color: "#000",
linewidth: 1,
nonstop: true,
stairs: true,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.PuWrg.SS01",
text: "PuWRG"
},
"AGENT.OBJECTS.House.SKL04_SK2.L13.TempWrgVl.MT01": {
visible: true,
axis: "right",
style: "Line",
color: "#FF2511",
linewidth: 1,
nonstop: false,
stairs: false,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.TempWrgVl.MT01",
text: "Temp. WRG Vorlauf"
},
"AGENT.OBJECTS.House.SKL04_SK2.L13.TempZulNachWRG.MT01": {
visible: true,
axis: "right",
style: "Line",
color: "#F99602",
linewidth: 1,
nonstop: false,
stairs: false,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.TempZulNachWRG.MT01",
text: "Temp. ZUL nach WRG"
},
"AGENT.OBJECTS.House.SKL04_SK2.L13.VtWrg.SS01": {
visible: true,
axis: "left",
style: "Line",
color: "#A5184A",
linewidth: 1,
nonstop: false,
stairs: true,
configname: "L13",
address: "AGENT.OBJECTS.House.SKL04_SK2.L13.VtWrg.SS01",
text: "VT WRG"
}
},
leftAxis: {
visible: "1",
autoScale: "1",
min: -3.7,
max: 37,
description: "Linke Achse"
},
rightAxis: {
visible: "1",
autoScale: "0",
min: 0,
max: 40,
description: "Rechte Achse"
},
time: {
startTime: 1453010899798,
endTime: 1453183699799,
lastTime: "1",
lastTimeValue: 2,
lastTimeUnit: "86400"
},
newnodes: {}
}
}
We have a web application which is using the php mail() function to send emails. Emails are received perfectly by all popular mail clients like gmail, yahoo, etc. but only outlook 365 not receiving any emails not even in Junk folder.
Amazon EC2, Ubuntu 14.04, Plesk 12, LAMP (Apache, MySQL and PHP)
We have checked email logs also but its not showing any errors. It looks like its sending email but its not received by Outlook 365 or they are blocking or something.
We have tried changing "\r\n" to "\n" but its also not working.
We have tried by changing SPF records but its also not working. http://365.webbrewers.com/blog/Lists/Posts/Post.aspx?ID=44
We have been trying to find out a solution everywhere including Microsoft Community, Plesk (Odin) Community, PHP Community, Ubuntu Community, Amazon EC2 Community and didn't find the work around.
In Java, is it legal to call remove on a collection when iterating through the collection using a foreach loop? For instance:
List names = ....
for (String name : names) {
// Do something
names.remove(name).
}
As an addendum, is it legal to remove items that have not been iterated over yet? For instance,
//Assume that the names list as duplicate entries
List names = ....
for (String name : names) {
// Do something
while (names.remove(name));
}
Answer
To safely remove from a collection while iterating over it you should use an Iterator.
For example:
List names = ....
Iterator i = names.iterator();
while (i.hasNext()) {
String s = i.next(); // must be called before you can call i.remove()
// Do something
i.remove();
}
From the Java Documentation :
The iterators returned by this class's iterator and listIterator
methods are fail-fast: if the list is structurally modified at any
time after the iterator is created, in any way except through the
iterator's own remove or add methods, the iterator will throw a
ConcurrentModificationException. Thus, in the face of concurrent
modification, the iterator fails quickly and cleanly, rather than
risking arbitrary, non-deterministic behavior at an undetermined time
in the future.
Perhaps what is unclear to many novices is the fact that iterating over a list using the for/foreach constructs implicitly creates an iterator which is necessarily inaccessible. This info can be found here
If I have a class named Object, what's the difference between creating an instance just like that:
#include
Object var;
main ()
{
var.test();
}
or
#include
main ()
{
Object* var = new Object();
var->test();
}
Which is the differente between a global object (which you can use wherever you want) and create a dynamic object in the main.cpp? In theory it should be the same, right? The both method can be used in any file.cpp.
I am writing a web application in php using Apache server. What I would like to do is have the index.php (and other files) display as *.aspx files, to confuse potential hackers.
Can this be done by editing the .htaccess file, and if so, what are the relevant lines to edit?
Answer
Serving the wrong file extension is not how you would achieve security, as it would not be enough to fool potential hackers. It might not even be enough to fool the guys at builtwith.com.
Instead of researching how to mislead the hackers with simple tricks, research on ways to secure your application better. You can start that at PHP.net and .
If you insist, you can use Apache mod_rewrite for that.
Something along this line (not tested):
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.aspx -f
RewriteRule ^(.+).aspx$ /$1.php [L,QSA]
Otherwise, you can also add mime-type in Apache to serve *aspx files as PHP.
AddType application/x-httpd-php .aspx
So, I try to make a Java Program, that when you run it, the first screen will be welcome, under it button "login", under it "register". And now I need to figure how if I press one of these buttons, how can I call new GUI, which I will define somewhere. (e.g) i call register button and it calls new gui where is normal things that asks you when you register(login,email,pass,date of birth)
EDIT: problem solved, but there is a one more thing. How can I close the first window?
This is my code so far:
import javax.swing.*;
import java.awt.*;
import java.awt.GridLayout;
import java.awt.BorderLayout;
import javax.swing.BorderFactory;
import java.awt.event.*;
import java.util.*;
import java.io.*;
import java.util.*;
import javax.swing.JFrame;
import java.awt.Dimension;
public class Gui extends JFrame
{
private JLabel lab1,lab2;
private JButton butt1,butt2;
private JPanel p1,p2;
public static void main(String[] args)
{
Gui okno = new Gui();
//vytáhne z defaultnÃho monitoru width a height
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int width = (int) screenSize.getWidth();
int height = (int) screenSize.getHeight();
//velikost okna
Dimension appSize = new Dimension(210,250);
okno.setPreferredSize(appSize);
//nastavenà na stred
okno.setLocation((width/2)-105,(height/2)-125);
okno.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
okno.setVisible(true);
//okno.setLocationRelativeTo(null); todle dá do stÅ™edu obrazovky jen prvnà body x a y od kterejch se to odvÃjÃ
okno.setResizable(false);
okno.pack();
}
public Gui(){
super("Jméno hry vole");
setLayout(new BorderLayout(20,20));
/////////////////////////////////////////////////////////////////
// p1
p1 = new JPanel();
add(p1,BorderLayout.NORTH);
lab1 = new JLabel("Welcome",SwingConstants.CENTER); //centr labelu
lab2 = new JLabel("Created by DECHKR",SwingConstants.CENTER); //centr labelu
lab1.setFont(new Font("Serif", Font.PLAIN, 36)); //velikost fontu
p1.add(lab1);
//p2
p2 = new JPanel(new GridLayout(2,1,0,5));
add(p2,BorderLayout.SOUTH);
Dimension d = new Dimension(210,75);
butt1 = new JButton("Login");
butt1.setPreferredSize(d);
butt2 = new JButton("Register");
butt2.setPreferredSize(d);
p2.add(butt1);
p2.add(butt2);
butt1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt){
//Gui okno = new Gui();
//System.exit(0); endne celej jvm proces
}
});
butt2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt){
}
});
}
Answer
I am still learning, but want to try and help.I would try making a new JFrame in the actionPerformed method of the listener. I also would probably make separate classes for your button action listeners otherwise you won't be able to perform separate task. I.E.
class button1Listener implements ActionListener {
public void actionPerformed(ActionEvent ev){
JFrame frame = new JFrame();
(ETC CODE...)
}
}
So I am adding conditional formatting to a column of cells that is dynamically created by the user with VBA. The problem I am having is that after the first format is added, any subsequent formatting will change the font color of the already formatted cells. There is some conditional formatting in the cells already that is copied from a master source that formats when cells = 0 or "Select One:" to be blue text in a yellow cell Below is the code I have so far:
With Range(Ltrs & 36, Ltrs & 41)
.FormatConditions.Add xlExpression, Formula1:="= $" & Ltrs & "$33 <> ""Custom" & OCV + 1 & """"
.FormatConditions(.FormatConditions.Count).SetFirstPriority
With .FormatConditions(1)
.Interior.Color = vbBlack
.Font.Color = vbBlack
.StopIfTrue = False
End With
End With
With Range(Ltrs & 42, Ltrs & 44)
.FormatConditions.Add xlExpression, Formula1:="=AND($" & Ltrs & "$29<>Repack1, $" & Ltrs & "$29<>Repack2)"
.FormatConditions(.FormatConditions.Count).SetFirstPriority
With .FormatConditions(1)
.Interior.Color = vbBlack
.Font.Color = vbBlack
.StopIfTrue = False
End With
End With
With Range(Ltrs & 45)
.FormatConditions.Add xlExpression, Formula1:="=AND($" & Ltrs & "$29<>Repack1, $" & Ltrs & "$29<>Repack2)"
.FormatConditions(.FormatConditions.Count).SetFirstPriority
With .FormatConditions(1)
.Interior.Color = vbBlack
.Font.Color = vbBlack
.StopIfTrue = False
End With
End With
With Range(Ltrs & 47)
.FormatConditions.Add Type:=xlTextString, String:="Enter", TextOperator:=xlContains
.FormatConditions(.FormatConditions.Count).SetFirstPriority
With .FormatConditions(1)
.Interior.Color = 13421823 'Light Red
.Font.Color = -14614363 'Dark Red/Brown
.StopIfTrue = False
End With
End With
This results in all cells with a 0 to be formatted with red text and all cells with "Select One:" to have black text while cells containing the value "Enter" have blue text. The strange thing is (at least to me) is that the interior cell colors are all still correct, it's just the font color that is wrong.
After first injecting himself at Oscorp, Curt created his own lab in the sewer system later in the movie. If he was the head of the lab at Oscorp, couldn't he have just kept everyone out of the lab (he had already done this previously) and done all of his testing there, instead of doing it in the sewer?
Answer
The Lizard often retreats to the sewers, lives in the sewers in his appearances in the comic "The Amazing Spider-Man".
One of the more famous Lizard storyline The Gauntlet has him trying to get humans to act like Lizards, turn them into lizards. He does this whilst hiding in the sewer.
Practically this is useful for a reptile who likes wet/humid conditions whilst also eliminating to some degree Spider-Man's main asset which is his agility given the cramped confines. It also allows him to navigate the city quickly without drawing attention to his form.
The current story arc in the Amazing Spider-Man, which start in issue 688 (I think) features the Lizard who is found living in the sewer.
So I think the film was trying to replicate the character from the comic for those comic fans out there, like myself.
I have just change my hosting, before all my PHP scripts worked fine
but now i get many mysql error like this:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near column = \'value\'
it seems that there is a double quote in some script
there is a way to resolve without update all my PHP scripts?
EDIT: example of PHP code
function test( $table,$column, $where ){
if( get_magic_quotes_gpc() ) { $where = strip_tags( trim( $where ) ); }
else{ $where = strip_tags( mysql_real_escape_string( trim( $where ) ) ); }
$where = "AND id = '" . $where . "' ";
$query = "SELECT " . $column . " FROM " . $table . " WHERE 1 " . $where . " LIMIT 1";
//...
How can you deserialize this json object below?
[{"id":"67","name":"TestString"}]
I tried to do this below but couldnt succeed...
success: function (data, status) {
$.each(data, function (dt) {
var mydata = data.d;
alert(mydata); // returns [{"id":"67","name":"TestString"}]
$("#txt_speciality").tokenInput("add", mydata.id);
});
}
here is the way I am creating the json object
[WebMethod]
public static string get_specialities(string ProfessionalID)
{
Database db = DatabaseFactory.CreateDatabase("Connection String2");
DbCommand dbCommand;
dbCommand = db.GetStoredProcCommand("Select_Professionals_Speciality");
db.AddInParameter(dbCommand, "prof_id", DbType.Int16, Convert.ToInt16(ProfessionalID));
IDataReader dr = db.ExecuteReader(dbCommand);
//[{ id: 3, name: "test3" }]
string return_str="[";
int i = 0;
while (dr.Read()) {
if (i > 0)
return_str += ",";
return_str += "{\"id\":\"" + dr["SpecialtyID"].ToString().Trim() + "\",\"name\":\"" + dr["SpecialtyName"].ToString().Trim() + "\"}";
i++;
}
return_str += "]";
return return_str;
}
Answer
You can do this with:
var mydata; // [{"id":"67","name":"TestString"}]
var json = $.parseJSON(mydata);
the json variable will contain the de-serialized json object
I am wondering if there is a library one can use that calculates elapsed time? Something like... if you pass it a long of milliseconds, you get a result like "2d 5h 12m 55s" (possibly even more formats similarly to SimpleDateFormatter).
I've heard of jodatime, but I've never used it. Can it be used for such calculations, or are there other more appropriate libraries?
It's not like I can't knock up a few methods myself, but I find myself doing this every now and then and that's why I'm wondering if something like this already exists.
Working on a python assignment and was curious as to what [:-1] means in the context of the following code: instructions = f.readline()[:-1]
Have searched on here on S.O. and on Google but to no avail. Would love an explanation!
Answer
It slices the string to omit the last character, in this case a newline character:
>>> 'test\n'[:-1]
'test'
Since this works even on empty strings, it's a pretty safe way of removing that last character, if present:
>>> ''[:-1]
''
This works on any sequence, not just strings.
For lines in a text file, I’d actually use line.rstrip('\n') to only remove a newline; sometimes the last line in the file doesn’t end in a newline character and using slicing then removes whatever other character is last on that line.
I came across some regular expressions that contain [^\\p{L}]. I understand that this is using some form of a Unicode category, but when I checked the documentation, I found only the following "L" categories:
Lu Uppercase letter UPPERCASE_LETTER
Ll Lowercase letter LOWERCASE_LETTER
Lt Titlecase letter TITLECASE_LETTER
Lm Modifier letter MODIFIER_LETTER
Lo Other letter OTHER_LETTER
What is L in this context?
Answer
Taken from this link: http://www.regular-expressions.info/unicode.html
Check the Unicode Character Properties section.
\p{L} matches a single code point in
the category "letter". If your input
string is à encoded as U+0061 U+0300,
it matches a without the accent. If
the input is à encoded as U+00E0, it
matches à with the accent. The reason
is that both the code points U+0061
(a) and U+00E0 (Ã ) are in the category
"letter", while U+0300 is in the
category "mark".
I have a script, TemplateLoader.js which loads 2 Mustache templates, and renders them on the page (or at least that's the goal).
My directory structure:
COMP266
Unit 4
scripts
mustache.min.js
TemplateLoader.js
PageUsingTemplateLoader.html
Inside of TemplateLoader (the object), I have the following chunk to load Mustache, and render the templates:
$.getScript("./scripts/mustache.min.js", function() {
$('head').html( Mustache.render(headTemplate, data) );
$('body').html( Mustache.render(bodyTemplate, data, uniqueBodyTemplate) );
});
This however, yields the following error in the developer console:
HTTP404: NOT FOUND - The server has not found anything matching the requested URI (Uniform Resource Identifier).
(XHR): GET - http://localhost:63342/COMP266/Unit%204/mustache.min.js?_=1450903391318
Oddly, it seems to have dropped the script folder completely from the path.
I decided to play around, so I changed the fetch path to (duplicating the script folder):
./scripts/scripts/mustache.min.js
But this yields:
HTTP404: NOT FOUND - The server has not found anything matching the requested URI (Uniform Resource Identifier).
(XHR): GET - http://localhost:63342/COMP266/Unit%204/scripts/scripts/mustache.min.js?_=1450903743022
Now it's listening! Unfortunately, this is obviously the wrong path.
I have no idea how to go about debugging this. It seems like jQuery is selectively dropping the scripts folder. That seems ridiculous, but just to make sure, I searched through the jQuery source, and couldn't find anything that would be doing the observed filtering of the path.
It's currently local, not hosted.
Can anyone give me a hint about what's going on here?
Answer
It turns out the issue was caused by me forgetting that my template added the mustache script (from a previous test), resulting in it being added twice.
I don't understand how this affected it though. It's not like the jQuery addition was succeeding while the template addition was causing the error, since changing the jQuery fetch path caused a direct change in the error message.
Sure enough though, when I removed the script import from the template, it worked.
I really don't understand how this caused a specific folder to be dropped from the path though.
I have been reading online and some places say it isn't possible, some say it is and then give an example and others refute the example, etc.
How do I declare a 2 dimensional array in JavaScript? (assuming it's possible)
How would I access its members? (myArray[0][1] or myArray[0,1]?)
Answer
var items = [
[1, 2],
[3, 4],
[5, 6]
];
console.log(items[0][0]); // 1
console.log(items[0][1]); // 2
console.log(items[1][0]); // 3
console.log(items[1][1]); // 4
console.log(items);I have a function which I want to take, as a parameter, a 2D array of variable size.
So far I have this:
void myFunction(double** myArray){
myArray[x][y] = 5;
etc...
}
And I have declared an array elsewhere in my code:
double anArray[10][10];
However, calling myFunction(anArray) gives me an error.
I do not want to copy the array when I pass it in. Any changes made in myFunction should alter the state of anArray. If I understand correctly, I only want to pass in as an argument a pointer to a 2D array. The function needs to accept arrays of different sizes also. So for example, [10][10] and [5][5]. How can I do this?
Answer
There are three ways to pass a 2D array to a function:
The parameter is a 2D array
int array[10][10];
void passFunc(int a[][10])
{
// ...
}
passFunc(array);
The parameter is an array containing pointers
int *array[10];
for(int i = 0; i < 10; i++)
array[i] = new int[10];
void passFunc(int *a[10]) //Array containing pointers
{
// ...
}
passFunc(array);
The parameter is a pointer to a pointer
int **array;
array = new int *[10];
for(int i = 0; i <10; i++)
array[i] = new int[10];
void passFunc(int **a)
{
// ...
}
passFunc(array);
I have a big object with much data. And i want to clone this in other variable. When i set some param of the instance B has the same result in the original object:
var obj = {a: 25, b: 50, c: 75};
var A = obj;
var B = obj;
A.a = 30;
B.a = 40;
alert(obj.a + " " + A.a + " " + B.a); // 40 40 40
My output should be 25 30 40.
Any ideas?
EDIT
Thanks Everyone. I change the code of dystroy and this is my result:
Object.prototype.clone = Array.prototype.clone = function()
{
if (Object.prototype.toString.call(this) === '[object Array]')
{
var clone = [];
for (var i=0; i
return clone;
}
else if (typeof(this)=="object")
{
var clone = {};
for (var prop in this)
if (this.hasOwnProperty(prop))
clone[prop] = this[prop].clone();
return clone;
}
else
return this;
}
var obj = {a: 25, b: 50, c: 75};
var A = obj.clone();
var B = obj.clone();
A.a = 30;
B.a = 40;
alert(obj.a + " " + A.a + " " + B.a);
var arr = [25, 50, 75];
var C = arr.clone();
var D = arr.clone();
C[0] = 30;
D[0] = 40;
alert(arr[0] + " " + C[0] + " " + D[0]);
I'm getting this error on my iPhone's safari, when doing localStorage.setItem('user',some string here):
Error: The quota has been exceeded.
setItem@[native code]
It is not private mode! What other circumstances can make localStorage not work?
I know there are many different causes for NPE but mine is slightly weird (At least to me).
So I have converted my Activities to Fragments successfully, but my problem appears to be coming from the function that displays the date. When the application is running, everything works just fine. But as soon as you press the back button. The app force closes, then in the log it says I'm getting NullPointerException at line 102. So looking at the code, I did research on this but unfortunately got nothing.
This is the line where the error is coming from when you press the back button.
getActivity().runOnUiThread(new Runnable(){
Also I have tried disabling the back button (As I'm building a launcher and it's not needed). But it doesn't seem to be working.
Here is the code for the whole date displaying method/function.
// (Calendar) Date function - Displays dateview on Card
final boolean keepRunning1 = true;
Thread thread_two = new Thread(){
@Override
public void run(){
while(keepRunning1){
// Make the thread wait half a second. If you want...
try {
Thread.sleep(500);
} catch (InterruptedException e) {
Toast.makeText(getActivity().getApplicationContext(), "Default Signature Fail", Toast.LENGTH_LONG).show();
e.printStackTrace();
}
getActivity().runOnUiThread(new Runnable(){
@Override
public void run(){
TextView date = (TextView) getView().findViewById(R.id.date);
date.setText(DateUtils.formatDateTime(getActivity().getBaseContext(), System.currentTimeMillis(),DateUtils.FORMAT_SHOW_WEEKDAY | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR));
}
});
}
}
};
thread_two.start();
Thanks for your time, hopefully you can shed some light on what I'm doing wrong.
Logcat -
05-23 21:17:33.216: E/AndroidRuntime(6906): java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.runOnUiThread(java.lang.Runnable)' on a null object reference
05-23 21:17:33.216: E/AndroidRuntime(6906): at com.activelauncher.fragments.UtilsFragment$2.run(UtilsFragment.java:102)
Answer
I'm almost sure that this is caused when the thread finish its work but the activity is no longer visible.
You should check if the getActivity() call return null, and ...
To apply corrections on your code, look at this:
// (Calendar) Date function - Displays dateview on Card
final boolean keepRunning1 = true;
Thread thread_two = new Thread(){
@Override
public void run(){
while(keepRunning1){
// Make the thread wait half a second. If you want...
try {
Thread.sleep(500);
} catch (InterruptedException e) {
Toast.makeText(getActivity().getApplicationContext(), "Default Signature Fail", Toast.LENGTH_LONG).show();
e.printStackTrace();
}
// here you check the value of getActivity() and break up if needed
if(getActivity() == null)
return;
getActivity().runOnUiThread(new Runnable(){
@Override
public void run(){
TextView date = (TextView) getView().findViewById(R.id.date);
date.setText(DateUtils.formatDateTime(getActivity().getBaseContext(), System.currentTimeMillis(),DateUtils.FORMAT_SHOW_WEEKDAY | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR));
}
});
}
}
};thread_two.start();
In hindsight I should not have enabled L build stuff.
I am new to programming and I created a new Android Studio project which is throwing the Gradle errror right away.
Errors are:
yellow bar at the top - Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly. Try again Open Event Log Show Log in Finder
messages gradle sync - compileSdkVersion android-L requires compiling with JDK-7. open sdk settings, open file.
tried looking through google and other comments but did not find much I could make sense of except for Android Studio - Gradle sync project failed
tried converting URL to 1.10 instead of 1.12 and syncing but that failed after syncing
I need help either getting L working or removing it so that a new studio project can compile to device without errors.
Answer
I too faced the same issue and after days of trouble I figured it out. Just check if Java is installed
java -version
Any version above JDK 6 is OK
open -a TextEdit ~/.bash_profile
export JAVA_HOME=$(/usr/libexec/java_home)
export JDK_HOME=$(/usr/libexec/java_home)
source ~/.bash_profile
Now try gradle sync now, you must be able to complete sync
I would think the following piece of code should work, but it doesn't (Edited: Now works in PHP 5.5+):
if (!empty($r->getError()))
Where getError() is simply:
public function getError()
{
return $this->error;
}
Yet I end up with this error:
can't use method return value in write context
What does this mean? Isn't this just a read?
Answer
empty() needs to access the value by reference (in order to check whether that reference points to something that exists), and PHP before 5.5 didn't support references to temporary values returned from functions.
However, the real problem you have is that you use empty() at all, mistakenly believing that "empty" value is any different from "false".
Empty is just an alias for !isset($thing) || !$thing. When the thing you're checking always exists (in PHP results of function calls always exist), the empty() function is nothing but a negation operator.
PHP doesn't have concept of emptyness. Values that evaluate to false are empty, values that evaluate to true are non-empty. It's the same thing. This code:
$x = something();
if (empty($x)) …
and this:
$x = something();
if (!$x) …
has always the same result, in all cases, for all datatypes (because $x is defined empty() is redundant).
Return value from the method always exists (even if you don't have return statement, return value exists and contains null). Therefore:
if (!empty($r->getError()))
is logically equivalent to:
if ($r->getError())
how do I apply css transition to a div which has initial width set as auto
However if I set the initial width to some number say 50px, the transition kicks in.
Here is the - DEMO
.container {
width: 200px;
background: red;
height: 50px;
}
.child1 {
background: black;
display: inline-block;
}
.child2 {
background: blue;
display: inline-block;
width: auto; /* this does not work */
/* width: 50px; */ /* this works */
float: right;
-webkit-transition: width 2s;
transition: width 2s;
}
.child2:hover {
width: 100px;
}
WHy would I choose to use Python's time vs datetime (and also mxDateTime) when either way you can get the same result? For example,
time.localtime()[7]
datetime.date.today().timetuple()[7]
yields the same, mxDateTime can also produce same result.
I'm used to doing print >>f, "hi there"
However, it seems that print >> is getting deprecated. What is the recommended way to do the line above?
Update:
Regarding all those answers with "\n"...is this universal or Unix-specific? IE, should I be doing "\r\n" on Windows?
Answer
This should be as simple as:
with open('somefile.txt', 'a') as the_file:
the_file.write('Hello\n')
From The Documentation:
Do not use
os.linesepas a line terminator when writing files opened in text mode (the default); use a single '\n' instead, on all platforms.
Some useful reading:
I have started on a program to count vowels and have seemed to be getting nowhere. I need to count vowels from a string and then display the vowels. I need to do this by storing the number of occurrences in variables. Like this :
a = 0
b = 0
....
then print the lowest.
Current code (its not that much ):
string = str(input("please input a string: "))
edit= ''.join(string)
print(edit)
I have tried a number of methods just by my self and don't seem to get anywhere.
Is it possible to store a pointer to an element inside of an std::set?
For instance take the following unsafe example...
std::vector vec;
//add a bunch of items
int* ptr = &vec[10];
//add more items
std::cout << *ptr << std::endl;
In this case the memory which ptr points to could have been invalidated by adding extra elements to the vector causing it to reallocate. However if I had used a linked list instead of a vector I believe this would have been safe since it does not need to reallocate the nodes.
I want to use an std::set to save memory when dealing with redundant strings. Would the following example be safe? I think it would be for std::set but not for std::unordered_set.
const char* makeString(const char* s)
{
static std::set strings_pool;
return strings_pool.insert(s).first->c_str();
}
If the string c is not already in the strings_pool it is inserted otherwise it returns an iterator to the string already in the pool. In either case I get the value of the iterator and return the pointer to underlying cstring. I think that this is a safe operation but can someone confirm it.
At this link http://en.cppreference.com/w/cpp/container/set/insert it says "No iterators or references are invalidated." I think this means I can do it.
Also under the documentation for std::unordered_set it says "References are not invalidated." Does this means it is safe to use std::unordered_set as well?
Answer
Yes, both set and unordered_set are safe in this regard. If references are not invalidated, your pointers also remain valid.
It's an easy property for the node-based collections to maintain; unlike vector there's no need for them to move values around in memory.
I'm really wanting to learn assembly. I'm pretty good at c/c++, but want a better understanding of what's going on at a lower level.
I realize that assembly related questions have been asked before, but I'm just looking for some direction that's particular to my situation:
I'm running windows 7, and am confused about how I should start working with assembly. Do I have to start with x64 because I'm running windows 7? Some people have said 'start with 32 bit first' - how do I go about doing this? What does my operating system have to do with my ability to write assembly for '32' or '64' bit. In fact, what does 'n bit' assembly mean, where n is a number??
Edit:
Here are some links that have helped me get started with assembly; others who are just getting started may find them helpful. I'll keep updating this list as I continue on my assembly journey :)
Note: As I've been learning, I've decided to focus on programming with masm32. Therefore most of the below resources focus on that.
Agner Fog's Software optimization resources, including some good stuff about calling conventions on different platforms (Windows vs. Linux/OS X), as well as a lot of examples of how to do specific things efficiently. Not great for total beginners, but great for intermediate to advanced readers.
(He also has detailed performance info for each instruction for Intel and AMD CPUs, excellent for serious performance micro-optimization. Some beginners might want to look at some of that to get started thinking about how CPUs work, and why you might do something one way instead of another.)
Answer
When people refer to 32-bit and 64-bit assembly, they're talking about which instruction set you'll use - they're also sometimes called Ia32 and x64 in the Intel case, which I presume you're asking about. There is a lot more going on in the 64-bit case, so starting with 32-bit is probably good; you just need to make sure you're assembling your program with a 32-bit assembler into a 32-bit binary. Windows will still know how to run it.
What I really recommend for getting started with assembly would be something with a simpler instruction set to get a handle on. Go learn MIPS assembly - the spim simulator is great and easy to use. If you really want to dive straight into the Intel assembly world, write yourself a little C program that calls your assembly routines for you; doing all the setup and teardown for a 'real program' is a big mess, and you won't even be able to get started there. So just write a C wrapper with main() in it, and compile and link that with the object files you get from writing your assembly code.
Please don't get in the habit of writing inline assembly in your C code - it's a code portability nightmare, and there's no reason for it.
You can download all of the Intel 64 and IA-32 Architectures Software Developer's Manuals to get started.
I wonder what is the difference between the following two code snippets:
and
I'm sure it does something when you use a special JavaScript library, but apart from that, does it validate the HTML or required for some other reason?
Answer
The tag allows you to click on the label, and it will be treated like clicking on the associated input element. There are two ways to create this association:
One way is to wrap the label element around the input element:
The other way is to use the for attribute, giving it the ID of the associated input:
This is especially useful for use with checkboxes and buttons, since it means you can check the box by clicking on the associated text instead of having to hit the box itself.
Read more about this element in MDN.
c has an indeterminate value in your for loop here:
for(int c; x < c; c++)
^
you need to initialize it to a value for example:
for(int c=2; x < c; c++)
it will need to be greater than 0(perhaps 2 since you probably don't want 1 as a divisor) since you are using it in the modulus operation here:
if (x%c==0)
and modulus by 0 is undefined behavior as per the draft C++ standard section 5.6 Multiplicative operators paragraph 4 says:
[...]If the second operand of / or % is zero the behavior is undefined.[...]
It looks like you may have flipped your ending condition and it should go from c < x instead of x < c.
I am working with a very wide dataset (1005 rows * 590,718 columns, 1.2G). Loading such a large dataset into a pandas dataframe result in code failure entirely due to insufficient memory.
I am aware that Spark is probably a good alternative to Pandas for dealing with large datasets, but is there any amenable solution in Pandas to reduce memory usage while loading large data?
Answer
You could use
pandas.read_csv(filename, chunksize = chunksize)
I'm relatively new to java, and the passing by reference without pointers confuses me a little. I wrote a function for homework that requires me to return the length of user input, and assign use input to an array that is passed in, when the method exits the user input array is lost, what is wrong.
public static int readArray(char[] intoArray)
{
char[] capture = captureInputAsCharArray(); //User input comes back as char[]
System.arraycopy(intoArray,0, capture, 0, capture.length);
return capture.length;
}
public static main(String[] args)
{
size = readArray(arrItem7); // item 7
System.out.println(size);
printOneInLine(arrItem7); // prints individual elements of array
}
Answer
Because you have the arguments to System.arraycopy() backwards.
http://download.oracle.com/javase/6/docs/api/java/lang/System.html
public static void arraycopy(Object src,
int srcPos,
Object dest,
int destPos,
int length)
Swap intoArray and capture:
System.arraycopy(capture,0, intoArray, 0, capture.length);
I am building a web app that imports data from data feeds in php/mysql. I import the data into a buffer/temp holding table. As each data format is different I choose the column to select based on the particular source.
I am having trouble getting this query to work in this context :
$stmt = $this->dbObj->prepare("SELECT mk.PK_phone_maker, b.?, b.phoneDescription
b.thumbPic,
FROM buffer_table b left join mobile_phone pm on b.? = pm.phoneModel
LEFT JOIN phone_maker mk on mk.CompanyName = b.?
WHERE pm.phoneModel is null
group by b.?");
$stmt->bind_param('ssss',$phoneModelField, $phoneModelField, $phnMakerField,$phoneModelField);
$stmt->execute();
I recieve the error msg:
Fatal error: Call to a member function bind_param() on a non-object
This refers to the line:
$stmt->bind_param('ssss',$phoneModelField, $phoneModelField,
And I assume this is because the "prepare" on my sql hasnt worked as $stmt is not an object
As such it appears to me that you can not bind parameters to select columns and join fields, you can only bind to the where clause. Am I right in this assertion or am I missing something?
Answer
Prepared statements only allow you to bind values, other constructs (such as fields, tables or functions, let alone whole bits of SQL) are not allowed.
I want to turn off PHP's magic quotes. I don't have access to php.ini.
When I tried to add php_flag magic_quotes_gpc off to my .htaccess file, I get a 500 internal server error. This is what my .htaccess file looks like:
AddType x-mapp-php5 .php
php_flag magic_quotes_gpc off
Then I tried to use ini_set('magic_quotes_gpc', 'O'), but that had no effect.
How do I turn magic quotes off?
Answer
As per the manual you can often install a custom php.ini on shared hosting, where mod_php isn't used and the php_value directive thus leads to an error. For suexec/FastCGI setups it is quite common to have a per-webspace php.ini in any case.
--
I don't think O (uppercase letter o) is a valid value to set an ini flag. You need to use a true/false, 1/0, or "on"/"off" value.
ini_set( 'magic_quotes_gpc', 0 ); // doesn't work
EDIT
After checking the list of ini settings, I see that magic_quotes_gpc is a PHP_INI_PERDIR setting (after 4.2.3), which means you can't change it with ini_set() (only PHP_INI_ALL settings can be changed with ini_set())
What this means is you have to use an .htaccess file to do this - OR - implement a script to reverse the effects of magic quotes. Something like this
if ( in_array( strtolower( ini_get( 'magic_quotes_gpc' ) ), array( '1', 'on' ) ) )
{
$_POST = array_map( 'stripslashes', $_POST );
$_GET = array_map( 'stripslashes', $_GET );
$_COOKIE = array_map( 'stripslashes', $_COOKIE );
}
I want to get all value of h1 tag and I found this article: getting all values from h1 tags using php
Then I tried to using:
include "functions/simple_html_dom.php";
function getTextBetweenTags($string, $tagname) {
// Create DOM from string
$html = str_get_html($string);
$titles = array();
// Find all tags
foreach($html->find($tagname) as $element) {
$titles[] = $element->plaintext;
}
return $titles;
}
echo getTextBetweenTags("http://mydomain.com/","h1");
?>
But it's not running and I get:
Notice: Array to string conversion in C:\xampp\htdocs\checker\abc.php
on line 14 Array
Plz help me fix it. I want to get all h1 tag of a website with input data is URL of that website. Thanks so much!
iOS6 ajax POST request caching is becoming a huge problem for our webApp. Most of our users have added the app to the home screen. Ever since the upgrade, most of the POST requests to the backend are not working and data is stale from over 6 days ago and counting. We are aware of two workarounds to resolve this, one is to change every POST request so that it's different by adding a timestamp or some random input to it, and the second is to disable caching on the webserver.
Both workarounds are detailed in the following post:
Is Safari on iOS 6 caching $.ajax results?
Turning off caching on the webserver would have solved the issue if it was set before the iOS6 upgrade (or right after). However, it seems any POST requests that were made since the upgrade and until the time we turned caching off from apps added to the home screen, are still cached! and we can't find a way to clear them. removing the home screen app and restarting the device doesn't do the trick! The only option we have is to change our URL or to add a timestamp to every request in addition to turning off caching on the webserver.
Does anyone know of a way to clear a home screen app cache, aside from restoring to factory? please provide details.
Warning to anyone who implemented a workaround by adding a timestamp to their requests without turning off caching on the server. If your app is added to the home screen, EVERY post response will now be cached and it doesn't seem to expire. Unless someone has a way to clear it, this looks like a potential memory leak!
Please take note of the updates at the end of this post.
Update: I have created a public project on GitHub for this library!
I would like to have a single template that once and for all takes care of pretty-printing all STL containers via operator<<. In pseudo code, I'm looking for something like this:
template
std::ostream & operator<<(std::ostream & o, const C & x)
{
o << open;
// for (typename C::const_iterator i = x.begin(); i != x.end(); i++) /* Old-school */
for (auto i = x.begin(); i != x.end(); i++)
{
if (i != x.begin()) o << delim;
o << *i;
}
o << close;
return o;
}
Now I've seen plenty of template magic here on SO that I never thought possible, so I'm wondering if anyone can suggest something that would match all containers C. Maybe something trait-ish that can figure out if something has the necessary iterator?
Many thanks!
Update (and solution)
After raising this problem again on Channel 9, I got a fantastic answer from Sven Groot, which, combined with a bit of SFINAE type traiting, appears to solve the problem in a completely general and nestable fashion. The delimiters may be individually specialised, an example specialization for std::set is included, as well as an example of using custom delimiters.
The helper "wrap_array()" can be used to print raw C arrays. Update: Pairs and tuples are available for printing; default delimiters are round brackets.
The enable-if type trait requires C++0x, but with some modifications it should be possible to make a C++98 version of this. Tuples require variadic templates, hence C++0x.
I have asked Sven to post the solution here so that I can accept it, but in the meantime I'd like to post the code myself for reference. (Update: Sven has now posted his code below, which I made the accepted answer. My own code uses container type traits, which work for me but may cause unexpected behaviour with non-container classes that provide iterators.)
Header (prettyprint.h):
#ifndef H_PRETTY_PRINT
#define H_PRETTY_PRINT
#include
#include
#include
#include
namespace std
{
// Pre-declarations of container types so we don't actually have to include the relevant headers if not needed, speeding up compilation time.
template class set;
}
namespace pretty_print
{
// SFINAE type trait to detect a container based on whether T::const_iterator exists.
// (Improvement idea: check also if begin()/end() exist.)
template
struct is_container_helper
{
private:
template static char test(typename C::const_iterator*);
template static int test(...);
public:
static const bool value = sizeof(test(0)) == sizeof(char);
};
// Basic is_container template; specialize to derive from std::true_type for all desired container types
template struct is_container : public ::std::integral_constant::value> { };
// Holds the delimiter values for a specific character type
template
struct delimiters_values
{
typedef TChar char_type;
const TChar * prefix;
const TChar * delimiter;
const TChar * postfix;
};
// Defines the delimiter values for a specific container and character type
template
struct delimiters
{
typedef delimiters_values type;
static const type values;
};
// Default delimiters
template struct delimiters { static const delimiters_values values; };
template const delimiters_values delimiters::values = { "[", ", ", "]" };
template struct delimiters { static const delimiters_values values; };
template const delimiters_values delimiters::values = { L"[", L", ", L"]" };
// Delimiters for set
template struct delimiters< ::std::set, char> { static const delimiters_values values; };
template const delimiters_values delimiters< ::std::set, char>::values = { "{", ", ", "}" };
template struct delimiters< ::std::set, wchar_t> { static const delimiters_values values; };
template const delimiters_values delimiters< ::std::set, wchar_t>::values = { L"{", L", ", L"}" };
// Delimiters for pair (reused for tuple, see below)
template struct delimiters< ::std::pair, char> { static const delimiters_values values; };
template const delimiters_values delimiters< ::std::pair, char>::values = { "(", ", ", ")" };
template struct delimiters< ::std::pair, wchar_t> { static const delimiters_values values; };
template const delimiters_values delimiters< ::std::pair, wchar_t>::values = { L"(", L", ", L")" };
// Functor to print containers. You can use this directly if you want to specificy a non-default delimiters type.
template, typename TDelimiters = delimiters>
struct print_container_helper
{
typedef TChar char_type;
typedef TDelimiters delimiters_type;
typedef std::basic_ostream & ostream_type;
print_container_helper(const T & container)
: _container(container)
{
}
inline void operator()(ostream_type & stream) const
{
if (delimiters_type::values.prefix != NULL)
stream << delimiters_type::values.prefix;
for (typename T::const_iterator beg = _container.begin(), end = _container.end(), it = beg; it != end; ++it)
{
if (it != beg && delimiters_type::values.delimiter != NULL)
stream << delimiters_type::values.delimiter;
stream << *it;
}
if (delimiters_type::values.postfix != NULL)
stream << delimiters_type::values.postfix;
}
private:
const T & _container;
};
// Type-erasing helper class for easy use of custom delimiters.
// Requires TCharTraits = std::char_traits and TChar = char or wchar_t, and MyDelims needs to be defined for TChar.
// Usage: "cout << pretty_print::custom_delims(x)".
struct custom_delims_base
{
virtual ~custom_delims_base() { }
virtual ::std::ostream & stream(::std::ostream &) = 0;
virtual ::std::wostream & stream(::std::wostream &) = 0;
};
template
struct custom_delims_wrapper : public custom_delims_base
{
custom_delims_wrapper(const T & t) : t(t) { }
::std::ostream & stream(::std::ostream & stream)
{
return stream << ::pretty_print::print_container_helper, Delims>(t);
}
::std::wostream & stream(::std::wostream & stream)
{
return stream << ::pretty_print::print_container_helper, Delims>(t);
}
private:
const T & t;
};
template
struct custom_delims
{
template custom_delims(const Container & c) : base(new custom_delims_wrapper(c)) { }
~custom_delims() { delete base; }
custom_delims_base * base;
};
} // namespace pretty_print
template
inline std::basic_ostream & operator<<(std::basic_ostream & stream, const pretty_print::custom_delims & p)
{
return p.base->stream(stream);
}
// Template aliases for char and wchar_t delimiters
// Enable these if you have compiler support
//
// Implement as "template const sdelims::type sdelims>::values = { ... }."
//template using pp_sdelims = pretty_print::delimiters;
//template using pp_wsdelims = pretty_print::delimiters;
namespace std
{
// Prints a print_container_helper to the specified stream.
template
inline basic_ostream & operator<<(basic_ostream & stream,
const ::pretty_print::print_container_helper & helper)
{
helper(stream);
return stream;
}
// Prints a container to the stream using default delimiters
template
inline typename enable_if< ::pretty_print::is_container::value, basic_ostream&>::type
operator<<(basic_ostream & stream, const T & container)
{
return stream << ::pretty_print::print_container_helper(container);
}
// Prints a pair to the stream using delimiters from delimiters>.
template
inline basic_ostream & operator<<(basic_ostream & stream, const pair & value)
{
if (::pretty_print::delimiters, TChar>::values.prefix != NULL)
stream << ::pretty_print::delimiters, TChar>::values.prefix;
stream << value.first;
if (::pretty_print::delimiters, TChar>::values.delimiter != NULL)
stream << ::pretty_print::delimiters, TChar>::values.delimiter;
stream << value.second;
if (::pretty_print::delimiters, TChar>::values.postfix != NULL)
stream << ::pretty_print::delimiters, TChar>::values.postfix;
return stream;
}
} // namespace std
// Prints a tuple to the stream using delimiters from delimiters>.
namespace pretty_print
{
struct tuple_dummy_t { }; // Just if you want special delimiters for tuples.
typedef std::pair tuple_dummy_pair;
template
struct pretty_tuple_helper
{
static inline void print(::std::basic_ostream & stream, const Tuple & value)
{
pretty_tuple_helper::print(stream, value);
if (delimiters::values.delimiter != NULL)
stream << delimiters::values.delimiter;
stream << std::get(value);
}
};
template
struct pretty_tuple_helper
{
static inline void print(::std::basic_ostream & stream, const Tuple & value) { stream << ::std::get<0>(value); }
};
} // namespace pretty_print
namespace std
{
template
inline basic_ostream & operator<<(basic_ostream & stream, const tuple & value)
{
if (::pretty_print::delimiters< ::pretty_print::tuple_dummy_pair, TChar>::values.prefix != NULL)
stream << ::pretty_print::delimiters< ::pretty_print::tuple_dummy_pair, TChar>::values.prefix;
::pretty_print::pretty_tuple_helper &, sizeof...(Args), TChar, TCharTraits>::print(stream, value);
if (::pretty_print::delimiters< ::pretty_print::tuple_dummy_pair, TChar>::values.postfix != NULL)
stream << ::pretty_print::delimiters< ::pretty_print::tuple_dummy_pair, TChar>::values.postfix;
return stream;
}
} // namespace std
// A wrapper for raw C-style arrays. Usage: int arr[] = { 1, 2, 4, 8, 16 }; std::cout << wrap_array(arr) << ...
namespace pretty_print
{
template
struct array_wrapper
{
typedef const T * const_iterator;
typedef T value_type;
array_wrapper(const T (& a)[N]) : _array(a) { }
inline const_iterator begin() const { return _array; }
inline const_iterator end() const { return _array + N; }
private:
const T * const _array;
};
} // namespace pretty_print
template
inline pretty_print::array_wrapper pretty_print_array(const T (& a)[N])
{
return pretty_print::array_wrapper(a);
}
#endif
Usage example:
#include
#include
#include
#include Further ideas for improvements:
std::tuple<...> in the same way is we have it for std::pair.Recent updates:
pretty_print namespace. Only the global stream operators and the pretty_print_array wrapper are in the global namespace.operator<< is now correctly in std.Notes:
std::copy() to get pretty-printing. I might reinstate the pretty iterator if this is a desired feature, but Sven's code below has the implementation.Thank you to everyone who contributed!
Note: If you are looking for a quick way to deploy custom delimiters, here is one way using type erasure. We assume that you have already constructed a delimiter class, say MyDel, like so:
struct MyDel { static const pretty_print::delimiters_values values; };
const pretty_print::delimiters_values MyDel::values = { "<", "; ", ">" };
Now we want to be able to write std::cout << MyPrinter(v) << std::endl; for some container v using those delimiters. MyPrinter will be a type-erasing class, like so:
struct wrapper_base
{
virtual ~wrapper_base() { }
virtual std::ostream & stream(std::ostream & o) = 0;
};
template
struct wrapper : public wrapper_base
{
wrapper(const T & t) : t(t) { }
std::ostream & stream(std::ostream & o)
{
return o << pretty_print::print_container_helper, Delims>(t);
}
private:
const T & t;
};
template
struct MyPrinter
{
template MyPrinter(const Container & c) : base(new wrapper(c)) { }
~MyPrinter() { delete base; }
wrapper_base * base;
};
template
std::ostream & operator<<(std::ostream & o, const MyPrinter & p) { return p.base->stream(o); }
Answer
This solution was inspired by Marcelo's solution, with a few changes:
#include
#include
#include
#include
#include
// This works similar to ostream_iterator, but doesn't print a delimiter after the final item
template >
class pretty_ostream_iterator : public std::iterator
{
public:
typedef TChar char_type;
typedef TCharTraits traits_type;
typedef std::basic_ostream ostream_type;
pretty_ostream_iterator(ostream_type &stream, const char_type *delim = NULL)
: _stream(&stream), _delim(delim), _insertDelim(false)
{
}
pretty_ostream_iterator& operator=(const T &value)
{
if( _delim != NULL )
{
// Don't insert a delimiter if this is the first time the function is called
if( _insertDelim )
(*_stream) << _delim;
else
_insertDelim = true;
}
(*_stream) << value;
return *this;
}
pretty_ostream_iterator& operator*()
{
return *this;
}
pretty_ostream_iterator& operator++()
{
return *this;
}
pretty_ostream_iterator& operator++(int)
{
return *this;
}
private:
ostream_type *_stream;
const char_type *_delim;
bool _insertDelim;
};
#if _MSC_VER >= 1400
// Declare pretty_ostream_iterator as checked
template
struct std::_Is_checked_helper > : public std::tr1::true_type
{
};
#endif // _MSC_VER >= 1400
namespace std
{
// Pre-declarations of container types so we don't actually have to include the relevant headers if not needed, speeding up compilation time.
// These aren't necessary if you do actually include the headers.
template class vector;
template class list;
template class set;
template class map;
}
// Basic is_container template; specialize to derive from std::true_type for all desired container types
template struct is_container : public std::false_type { };
// Mark vector as a container
template struct is_container > : public std::true_type { };
// Mark list as a container
template struct is_container > : public std::true_type { };
// Mark set as a container
template struct is_container > : public std::true_type { };
// Mark map as a container
template struct is_container > : public std::true_type { };
// Holds the delimiter values for a specific character type
template
struct delimiters_values
{
typedef TChar char_type;
const TChar *prefix;
const TChar *delimiter;
const TChar *postfix;
};
// Defines the delimiter values for a specific container and character type
template
struct delimiters
{
static const delimiters_values values;
};
// Default delimiters
template struct delimiters { static const delimiters_values values; };
template const delimiters_values delimiters::values = { "{ ", ", ", " }" };
template struct delimiters { static const delimiters_values values; };
template const delimiters_values delimiters::values = { L"{ ", L", ", L" }" };
// Delimiters for set
template struct delimiters, char> { static const delimiters_values values; };
template const delimiters_values delimiters, char>::values = { "[ ", ", ", " ]" };
template struct delimiters, wchar_t> { static const delimiters_values values; };
template const delimiters_values delimiters, wchar_t>::values = { L"[ ", L", ", L" ]" };
// Delimiters for pair
template struct delimiters, char> { static const delimiters_values values; };
template const delimiters_values delimiters, char>::values = { "(", ", ", ")" };
template struct delimiters, wchar_t> { static const delimiters_values values; };
template const delimiters_values delimiters, wchar_t>::values = { L"(", L", ", L")" };
// Functor to print containers. You can use this directly if you want to specificy a non-default delimiters type.
template, typename TDelimiters = delimiters >
struct print_container_helper
{
typedef TChar char_type;
typedef TDelimiters delimiters_type;
typedef std::basic_ostream& ostream_type;
print_container_helper(const T &container)
: _container(&container)
{
}
void operator()(ostream_type &stream) const
{
if( delimiters_type::values.prefix != NULL )
stream << delimiters_type::values.prefix;
std::copy(_container->begin(), _container->end(), pretty_ostream_iterator(stream, delimiters_type::values.delimiter));
if( delimiters_type::values.postfix != NULL )
stream << delimiters_type::values.postfix;
}
private:
const T *_container;
};
// Prints a print_container_helper to the specified stream.
template
std::basic_ostream& operator<<(std::basic_ostream &stream, const print_container_helper &helper)
{
helper(stream);
return stream;
}
// Prints a container to the stream using default delimiters
template
typename std::enable_if::value, std::basic_ostream&>::type
operator<<(std::basic_ostream &stream, const T &container)
{
stream << print_container_helper(container);
return stream;
}
// Prints a pair to the stream using delimiters from delimiters>.
template
std::basic_ostream& operator<<(std::basic_ostream &stream, const std::pair &value)
{
if( delimiters, TChar>::values.prefix != NULL )
stream << delimiters, TChar>::values.prefix;
stream << value.first;
if( delimiters, TChar>::values.delimiter != NULL )
stream << delimiters, TChar>::values.delimiter;
stream << value.second;
if( delimiters, TChar>::values.postfix != NULL )
stream << delimiters, TChar>::values.postfix;
return stream;
}
// Used by the sample below to generate some values
struct fibonacci
{
fibonacci() : f1(0), f2(1) { }
int operator()()
{
int r = f1 + f2;
f1 = f2;
f2 = r;
return f1;
}
private:
int f1;
int f2;
};
int main()
{
std::vector v;
std::generate_n(std::back_inserter(v), 10, fibonacci());
std::cout << v << std::endl;
// Example of using pretty_ostream_iterator directly
std::generate_n(pretty_ostream_iterator(std::cout, ";"), 20, fibonacci());
std::cout << std::endl;
}
Like Marcelo's version, it uses an is_container type trait that must be specialized for all containers that are to be supported. It may be possible to use a trait to check for value_type, const_iterator, begin()/end(), but I'm not sure I'd recommend that since it might match things that match those criteria but aren't actually containers, like std::basic_string. Also like Marcelo's version, it uses templates that can be specialized to specify the delimiters to use.
The major difference is that I've built my version around a pretty_ostream_iterator, which works similar to the std::ostream_iterator but doesn't print a delimiter after the last item. Formatting the containers is done by the print_container_helper, which can be used directly to print containers without an is_container trait, or to specify a different delimiters type.
I've also defined is_container and delimiters so it will work for containers with non-standard predicates or allocators, and for both char and wchar_t. The operator<< function itself is also defined to work with both char and wchar_t streams.
Finally, I've used std::enable_if, which is available as part of C++0x, and works in Visual C++ 2010 and g++ 4.3 (needs the -std=c++0x flag) and later. This way there is no dependency on Boost.
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