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 can I do this in Python?

Answer 1

oneliner:

>>> s = 'badcfe'
>>> ''.join([ s[x:x+2][::-1] for x in range(0, len(s), 2) ])
'abcdef'

• s[x:x+2] returns string slice from x to x+2; it is safe for odd len(s).
• [::-1] reverses the string in Python
• range(0, len(s), 2) returns 0, 2, 4, 6 ... while x < len(s)