How do I compare two strings in python for differences?

Question

I've got two strings like this:

string1 = "Foo Bar"
string2 = "Foo BBar"

How do I compare them to see the difference? If I just compare string1[i] to string2[i] I just end up with the last Word "Bar" being different, as, for example, string1[5] isn't the same as string2[5], and so on.

Is there a way to just output "B"?

• Barmar: Take a look at difflib

Answer 1

As suggested by @barmar, difflib may be the way to go here.

So here's a snippet just to fit your example, but it may not be suited for all your cases.

import difflib
string1 = "Foo Bar"
string2 = "Foo BBar"
[d[2:] for d in difflib.ndiff(string1, string2) if d.startswith("+")]
# ['B']

If you want to know more about it, please read the doc or this answer.