How to determine whether a substring is in a different string [duplicate]

Answer 1

If you're looking for more than a True/False, you'd be best suited to use the re module, like:

import re
search="please help me out"
fullstring="please help me out so that I could solve this"
s = re.search(search,fullstring)
print(s.group())

s.group() will return the string "please help me out".

Answer 2

Instead Of using find(), One of the easy way is the Use of 'in' as above.

if 'substring' is present in 'str' then if part will execute otherwise else part will execute.

Answer 3

People mentioned string.find(), string.index(), and string.indexOf() in the comments, and I summarize them here (according to the Python Documentation):

First of all there is not a string.indexOf() method. The link posted by Deviljho shows this is a JavaScript function.

Second the string.find() and string.index() actually return the index of a substring. The only difference is how they handle the substring not found situation: string.find() returns -1 while string.index() raises an ValueError.

Answer 4

In [7]: substring = "please help me out"

In [8]: string = "please help me out so that I could solve this"

In [9]: substring in string
Out[9]: True

Answer 5

foo = "blahblahblah"
bar = "somethingblahblahblahmeep"
if foo in bar:
    # do something

(By the way - try to not name a variable string, since there's a Python standard library with the same name. You might confuse people if you do that in a large project, so avoiding collisions like that is a good habit to get into.)

Answer 6

Thought I would add this in case you are looking at how to do this for a technical interview where they don't want you to use Python's built-in function in or find, which is horrible, but does happen:

string = "Samantha"
word = "man"

def find_sub_string(word, string):
  len_word = len(word)  #returns 3

  for i in range(len(string)-1):
    if string[i: i + len_word] == word:
  return True

  else:
    return False