Python – Test substring order
Given two strings, check if substring characters occur in correct order in string.
Input : test_str = ‘geeksforgeeks’, K = ‘sees’
Output : True
Explanation : “s” after that “ee” and then “s” is present in order in string 1.Input : test_str = ‘geeksforgeeks’, K = ‘seef’
Output : False
Explanation : Unordered String.
Method #1 : Using join() + generator expression + in operator
In this, we check we join all the characters which occur in substring using join(), post that check if substring is present using in operator.
Python3
# Python3 code to demonstrate working of # Test substring order# Using join() + in operator + generator expression # initializing stringtest_str = 'geeksforgeeks' # printing original stringprint("The original string is : " + str(test_str)) # initializing substringK = 'seek' # concatenating required characters temp = lambda sub: ''.join(chr for chr in sub if chr in set(K)) # checking in orderres = K in temp(test_str) # printing result print("Is substring in order : " + str(res)) |
Output
The original string is : geeksforgeeks Is substring in order : True
Method #2 : Using all() + next() + generator expression
In this, we get the string with just substring characters using next() and generator expression, to check for order, all() operation is used for each character in substring.
Python3
# Python3 code to demonstrate working of # Test substring order# Using all() + next() + generator expression # initializing stringtest_str = 'geeksforgeeks' # printing original stringprint("The original string is : " + str(test_str)) # initializing substringK = 'seek' # concatenating required characters using next()# all() used to test ordertest_str = iter(test_str)res = all(next((ele for ele in test_str if ele == chr), None) is not None for chr in K) # printing result print("Is substring in order : " + str(res)) |
Output
The original string is : geeksforgeeks Is substring in order : True
