Python | Check if a Substring is Present in a Given String
Given two strings, check if s1 is there in s2.
Examples:
Input : s1 = geeks s2=geeks for geeks Output : yes Input : s1 = geek s2=geeks for geeks Output : yes
We can iteratively check for every word, but Python provides us an inbuilt function find() which checks if a substring is present in the string, which is done in one line.
find() function returns -1 if it is not found, else it returns the first occurrence, so using this function this problem can be solved.
Method 1: Using user defined function.
# function to check if small string is # there in big stringdef check(string, sub_str): if (string.find(sub_str) == -1): print("NO") else: print("YES") # driver codestring = "geeks for geeks"sub_str ="geek"check(string, sub_str) |
Output:
YES
Method 2: Using “count()” method:-
def check(s2, s1): if (s2.count(s1)>0): print("YES") else: print("NO") s2 = "A geek in need is a geek indeed"s1 ="geek"check(s2, s1) |
Output:
YES
Method 3: Using regular expressions
RegEx can be used to check if a string contains the specified search pattern. Python has a built-in package called re, which can be used to work with Regular Expressions.
# When you have imported the re module, you can start using regular expressions.import re # Take input from usersMyString1 = "A geek in need is a geek indeed"MyString2 ="geek" # re.search() returns a Match object if there is a match anywhere in the stringif re.search( MyString2, MyString1 ): print("YES,string '{0}' is present in string '{1}' " .format(MyString2,MyString1))else: print("NO,string '{0}' is not present in string {1} " .format(MyString2, MyString1) ) |
Output:
YES,string 'geek' is present in string 'A geek in need is a geek indeed'
Last Updated on October 28, 2021 by admin