How can I tell if a python variable is a string or a list?

Question

I have a routine that takes a list of strings as a parameter, but I'd like to support passing in a single string and converting it to a list of one string. For example:

def func( files ):     for f in files:         doSomethingWithFile( f )  func( ['file1','file2','file3'] )  func( 'file1' ) # should be treated like ['file1'] 

How can my function tell whether a string or a list has been passed in? I know there is a type function, but is there a "more pythonic" way?

Answer 1

isinstance(your_var, basestring) 

Answer 2

Well, there's nothing unpythonic about checking type. Having said that, if you're willing to put a small burden on the caller:

def func( *files ):     for f in files:          doSomethingWithFile( f )  func( *['file1','file2','file3'] ) #Is treated like func('file1','file2','file3') func( 'file1' ) 

I'd argue this is more pythonic in that "explicit is better than implicit". Here there is at least a recognition on the part of the caller when the input is already in list form.