Question

Suppose I want to change ‘abc’ to ‘bac’ in Python. What would be the best way to do it?

I am thinking of the following

tmp = list('abc')
tmp[0],tmp[1] = tmp[1],tmp[0]
result = ''.join(tmp)

Answer 1

You are never editing a string “in place”, strings are immutable.

You could do it with a list but that is wasting code and memory.

Why not just do:

x = 'abc'
result = x[1] + x[0] + x[2:]

or (personal fav)

import re
re.sub('(.)(.)', r'\2\1','abc')

This might be cheating, but if you really want to edit in place, and are using 2.6 or older, then use MutableString(this was deprecated in 3.0).

from UserString import MutableString
x = MutableString('abc')
x[1], x[0] = x[0], x[1]
>>>>'bac'

With that being said, solutions are generally not as simple as ‘abc’ = ‘bac’ You might want to give us more details on how you need to split up your string. Is it always just swapping first digits?