While we believe that this content benefits our community, we have not yet thoroughly reviewed it. If you have any suggestions for improvements, please let us know by clicking the “report an issue“ button at the bottom of the tutorial.
A substring is the part of a string. Python string provides various methods to create a substring, check if it contains a substring, index of substring etc. In this tutorial, we will look into various operations related to substrings.
Let’s first look at two different ways to create a substring.
s = 'My Name is Pankaj' # create substring using slice name = s[11:] print(name) # list of substrings using split l1 = s.split() print(l1)
Pankaj ['My', 'Name', 'is', 'Pankaj']
We can use in operator or find() function to check if substring is present in the string or not.
s = 'My Name is Pankaj' if 'Name' in s: print('Substring found') if s.find('Name') != -1: print('Substring found')
Note that find() function returns the index position of the substring if it’s found, otherwise it returns -1.
We can use count() function to find the number of occurrences of a substring in the string.
s = 'My Name is Pankaj' print('Substring count =', s.count('a')) s = 'This Is The Best Theorem' print('Substring count =', s.count('Th'))
Substring count = 3 Substring count = 3
There is no built-in function to get the list of all the indexes for the substring. However, we can easily define one using find() function.
def find_all_indexes(input_str, substring): l2 =  length = len(input_str) index = 0 while index < length: i = input_str.find(substring, index) if i == -1: return l2 l2.append(i) index = i + 1 return l2 s = 'This Is The Best Theorem' print(find_all_indexes(s, 'Th'))
[0, 8, 17]
You can checkout complete python script and more Python examples from our GitHub Repository.
Thanks for learning with the DigitalOcean Community. Check out our offerings for compute, storage, networking, and managed databases.