python: how to identify if a variable is an array or a scalar

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I have a function that takes the
argument NBins. I want to make a call to this function with a
scalar 50 or an array [0, 10, 20, 30].
How can I identify within the function, what the length of
NBins is? or said differently, if it is a scalar or a vector?

I tried
this:

>>>
            N=[2,3,5]
>>> P = 5
>>>
            len(N)
3
>>> len(P)
Traceback (most recent call
            last):
 File "", line 1, in 
TypeError:
            object of type 'int' has no len()

>>>
            

As you see, I can't
apply len to P, since it's not an
array.... Is there something like isarray or
isscalar in
python?

thanks

Answer

>>> isinstance([0, 10,
            20, 30], list)
True
>>> isinstance(50,
            list)

False

To
support any type of sequence, check collections.Sequence
instead of
list.

note:
isinstance also supports a tuple of classes, check
type(x) in (..., ...) should be avoided and is
unnecessary.

You may also wanna check
not isinstance(x, (str, unicode))