Check if input is a list/tuple of strings or a single string

You can check if a variable is a string or unicode string with

• Python 3:

    isinstance(some_object, str)

• Python 2:

    isinstance(some_object, basestring)

This will return True for both strings and unicode strings

As you are using python 2.5, you could do something like this:

if isinstance(some_object, basestring):
    ...
elif all(isinstance(item, basestring) for item in some_object): # check iterable for stringness of all items. Will raise TypeError if some_object is not iterable
    ...
else:
    raise TypeError # or something along that line

Stringness is probably not a word, but I hope you get the idea

isinstance is an option:

In [2]: isinstance("a", str)
Out[2]: True

In [3]: isinstance([], str)
Out[3]: False

In [4]: isinstance([], list)
Out[4]: True

In [5]: isinstance("", list)
Out[5]: False

Type checking:

def func(arg):
    if not isinstance(arg, (list, tuple)):
        arg = [arg]
    # process

func('abc')
func(['abc', '123'])

Varargs:

def func(*arg):
    # process

func('abc')
func('abc', '123')
func(*['abc', '123'])

As I like to keep things simple, here is the shortest form that is compatible with both 2.x and 3.x:

# trick for py2/3 compatibility
if 'basestring' not in globals():
   basestring = str

v = "xx"

if isinstance(v, basestring):
   print("is string")

>>> type('abc') is str
True
>>> type(['abc']) is str
False

This code is compatible with Python 2 and 3