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

Loop over length of string by twos and swap:

def oddswap(st):
    s = list(st)
    for c in range(0,len(s),2):
        t=s[c]
        s[c]=s[c+1]
        s[c+1]=t

    return "".join(s)

giving:

>>> s
'foobar'
>>> oddswap(s)
'ofbora'

and fails on odd-length strings with an IndexError exception.