What is the simplest way to swap each pair of adjoining chars in a string with Python?

Question

I want to swap each pair of characters in a string. \'2143\' becomes \'1234\', \'badcfe\' becomes \'abcdef\'.

How

Answer 1

>>> import ctypes
>>> s = 'abcdef'
>>> mutable = ctypes.create_string_buffer(s)
>>> for i in range(0,len(s),2):
>>>     mutable[i], mutable[i+1] = mutable[i+1], mutable[i]
>>> s = mutable.value
>>> print s
badcfe