Python | Check if given string can be formed by concatenating string elements of list

Given a string ‘str’ and a list of string elements, write a Python program to check whether given string can be formed by concatenating the string elements of list or not.

Examples:

Input : str = 'python'
        lst = ['co', 'de', 'py', 'ks', 'on']
Output : False

Input : str = 'geeks'
        lst = ['for', 'ge', 'abc', 'ks', 'e', 'xyz']
Output : True

 
Approach #1 : Using itertools.permuations

We can use all the permutations of the given list and then perform join operation on them. If any join result is equal to the given string, return true, otherwise false.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 program to Check if given string can 
# be formed by concatenating string elements 
# of list
from itertools import permutations
  
def checkList(str, lst):
    for i in range(2, len(lst)+1):
        for perm in permutations(lst, i):
            if ''.join(perm)== str:
                return True
                  
    return False
      
# Driver code
str = 'geeks'
lst = ['for', 'ge', 'abc', 'ks', 'e', 'xyz']
print(checkList(str, lst))

chevron_right


Output:

True

 
Approach #2 : Python RegEx

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 program to Check if given string can 
# be formed by concatenating string elements 
# of list
import re 
  
def checkList(str, lst):
  
    r = re.compile("(?:" + "|".join(lst) + ")*$")
    if r.match(str) != None:
        return True
          
    return False
      
# Driver code
str = 'geeks'
lst = ['for', 'ge', 'abc', 'ks', 'e']
print(checkList(str, lst))

chevron_right


Output:

True


My Personal Notes arrow_drop_up


If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :

Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.