Python | Pair Kth character with each element

Last Updated : 22 Apr, 2020

Sometimes, while working with Python, we can have a problem in which we need to perform the pairing of each character with every other in String. This can have application in many domains including web development and day-day. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This task can be performed using loop. This a brute force manner in which this task can be performed. In this, we iterate each character and append the Kth letter to each and construct a list.

# Python3 code to demonstrate working of  
# Pair Kth character with each element 
# Using loop 
  
# initializing string 
test_str = "geeksforgeeks"
  
# printing original string 
print("The original string is : " + test_str) 
  
# initializing K  
K = 4
  
# Pair Kth character with each element 
# Using loop 
res = [] 
for ele in test_str: 
        res.append(test_str[K] + ele) 
  
# printing result  
print("List after pairing : " + str(res))  

Output :

The original string is : geeksforgeeks
List after pairing : ['sg', 'se', 'se', 'sk', 'ss', 'sf', 'so', 'sr', 'sg', 'se', 'se', 'sk', 'ss']

Method #2 : Using join() + zip() + cycle()
The combination of above functions can be used to perform this task. In this, we perform the task of joining using join(). The task of pairing with all is done with zip() + cycle().

# Python3 code to demonstrate working of  
# Pair Kth character with each element 
# Using join() + zip() + cycle() 
from itertools import cycle 
  
# initializing string 
test_str = "geeksforgeeks"
  
# printing original string 
print("The original string is : " + test_str) 
  
# initializing K  
K = 4
  
# Pair Kth character with each element 
# Using join() + zip() + cycle() 
res = list(map(''.join, zip(cycle(test_str[K]), test_str))) 
  
# printing result  
print("List after pairing : " + str(res))  

Output :

The original string is : geeksforgeeks
List after pairing : ['sg', 'se', 'se', 'sk', 'ss', 'sf', 'so', 'sr', 'sg', 'se', 'se', 'sk', 'ss']

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