Changing one character in a string

python string
kostia picture kostia · Aug 4, 2009 · Viewed 822.8k times · Source

What is the easiest way in Python to replace a character in a string?

For example:

text = "abcdefg";
text[1] = "Z";
           ^

Answer

scvalex picture scvalex · Aug 4, 2009

Don't modify strings.

Work with them as lists; turn them into strings only when needed.

>>> s = list("Hello zorld")
>>> s
['H', 'e', 'l', 'l', 'o', ' ', 'z', 'o', 'r', 'l', 'd']
>>> s[6] = 'W'
>>> s
['H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd']
>>> "".join(s)
'Hello World'

Python strings are immutable (i.e. they can't be modified). There are a lot of reasons for this. Use lists until you have no choice, only then turn them into strings.

Related questions

Does Python have a string 'contains' substring method?

I'm looking for a string.contains or string.indexof method in Python. I want to do: if not somestring.contains("blah"): continue

Read More
How to read a file line-by-line into a list?

How do I read every line of a file in Python and store each line as an element in a list? I want to read the file line by line and append each line to the end of the list.

Read More
Converting integer to string in Python

I want to convert an integer to a string in Python. I am typecasting it in vain: d = 15 d.str() When I try to convert it to string, it's showing an error like int doesn't have any attribute called str.

Read More