r - How to trim leading and trailing whitespace?

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I am having some troubles with leading
and trailing whitespace in a data.frame.

Eg I like to take a look
at a specific row in a data.frame
based on a certain condition:

>
            myDummy[myDummy$country == c("Austria"),c(1,2,3:7,19)] 

[1]
            codeHelper country dummyLI dummyLMI dummyUMI 
[6] dummyHInonOECD dummyHIOECD
            dummyOECD 
<0 rows> (or 0-length
            row.names)

I was
wondering why I didn't get the expected output since the country Austria obviously
existed in my data.frame. After looking through my code history
and trying to figure out what went wrong I
tried:

>
            myDummy[myDummy$country == c("Austria "),c(1,2,3:7,19)]
 codeHelper country
            dummyLI dummyLMI dummyUMI dummyHInonOECD dummyHIOECD
18 AUT Austria 0 0 0 0
            1
 dummyOECD
18
            1

All I have changed
in the command is an additional whitespace after Austria.

Further annoying problems obviously
arise. Eg when I like to merge two frames based on the country column. One
data.frame uses "Austria " while the
other frame has "Austria". The matching doesn't
work.

1. Is there a nice way
   to 'show' the whitespace on my screen so that i am aware of the problem?
   


2. And can I remove the leading and trailing whitespace in
   R?

So far I used to write
a simple Perl script which removes the whitespace but it would
be nice if I can somehow do it inside R.

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class="normal">Answer

Probably
the best way is to handle the trailing whitespaces when you read your data file. If you
use read.csv or read.table you can set
the
parameterstrip.white=TRUE.

If
you want to clean strings afterwards you could use one of these
functions:

# returns string w/o
            leading whitespace
trim.leading <- function (x) sub("^\\s+", "",
            x)

# returns string w/o trailing whitespace
trim.trailing
            <- function (x) sub("\\s+$", "", x)

# returns string w/o leading
            or trailing whitespace

trim <- function (x) gsub("^\\s+|\\s+$",
            "", x)

To use one of
these functions on
myDummy$country:

            myDummy$country <-
            trim(myDummy$country)

/>

To 'show' the whitespace you could
use:

            paste(myDummy$country)

which
will show you the strings surrounded by quotation marks (") making whitespaces easier to
spot.