Replace multiple characters in a string in python at once

Question

In my code, I need to replace all Is with 1s, and all os with 0s. I can do it in two statements, which is code as follows:

stringtochange=raw_input("What do you want to change?")
print stringtochange.replace("I","1")
print stringtochange.replace("o","0")

but I need it to do it all in one fell swoop. Any ideas?

• John Machin: Please edit your question to include a Python2.x or Python3.x tag -- the args for str.translate have changed a lot between Py2 and Py3
• byu: @johnmachin will do, sorry about that

Answer 1

You can use string.translate:

s = "IslkdoIoooI"
import string
s.translate(string.maketrans("Io", "10"))
# '1slkd010001'

Answer 2

You can map multiple values using list comprehension:

str = "Itesto"
source = ['I', 'o']
dest = ['1', '0']
''.join([dest[source.index(i)] if i in source else i for i in str])
>> '1test0'

• John Machin: Good answer -- Some remarks on style etc: Don't use the name str for your own objects -- it masks out the built-in type. Also it's OK to use one-letter names provided their scope is not very wide; however i (and j and k) signify "index" to most people. Your i is a character; calling it c would be better.

Answer 3

This alternative uses a dict to map source characters to replacement characters:

>>> s = "HIJnop"; xmap = {"I": "1", "o": "0"}; ''.join([xmap.get(c, c) for c in s])
'H1Jn0p'