'in-place' string modifications in Python

Question

In Python, strings are immutable.

What is the standard idiom to walk through a string character-by-character and modify it?

The only methods I can think of a

Answer 1

Assigning a particular character to a particular index in a string is not a particularly common operation, so if you find yourself needing to do it, think about whether there may be a better way to accomplish the task. But if you do need to, probably the most standard way would be to convert the string to a list, make your modifications, and then convert it back to a string.

s = 'abcdefgh'
l = list(s)
l[3] = 'r'
s2 = ''.join(l)

EDIT: As posted in bstpierre's answer, bytearray is probably even better for this task than list, as long as you're not working with Unicode strings.

s = 'abcdefgh'
b = bytearray(s)
b[3] = 'r'
s2 = str(b)