How do I check if a given Python string is a substring of another one?

Question

I have two strings and I would like to check whether the first is a substring of the other. Does Python have such a built-in functionality?

It is already answered here:http://stackoverflow.com/questions/2590503/how-to-find-whether-a-string-in-a-another-string — Saurabh Gokhale, Feb 28 '11 at 15:15

score 513 · Accepted Answer · answered Feb 28 '11 at 15:14

513

Try using in like this:

>>> x = 'hello'
>>> y = 'll'
>>> y in x
True

answered Feb 28 '11 at 15:14

Andrew Hare

7

What about complexity as compare to using regex? – Piyush S. Wanare Oct 13 '17 at 16:50

score 55 · Answer 2 · answered Feb 28 '11 at 15:14

55

Try

isSubstring = first in theOther

answered Feb 28 '11 at 15:14

Martin Stone

score 43 · Answer 3 · edited Nov 08 '17 at 18:06

43

string.find("substring") will help you. This function returns -1 when there is no substring.

edited Nov 08 '17 at 18:06

cs95

answered Feb 28 '11 at 15:16

Daniel Wehner

What if I was looking for the position of the third or fourth occurrence of 'e', or the likes thereof? – Musixauce3000 Apr 14 '16 at 22:37
python supports regulary expressions (regex). What ever you are looking for make a regex-group auto of it, afterwards you can select the 3rd group. – Cutton Eye Feb 08 '18 at 15:35

3 Answers3