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Python program to concatenate every elements across lists
  • Last Updated : 11 Oct, 2020
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Given 2 lists, perform concatenations of all strings with each other across list.

Input : test_list1 = [“gfg”, “is”, “best”], test_list2 = [“love”, “CS”] 
Output : [‘gfg love’, ‘gfg CS’, ‘is love’, ‘is CS’, ‘best love’, ‘best CS’] 
Explanation : All strings are coupled with one another.

Input : test_list1 = [“gfg”, “best”], test_list2 = [“love”, “CS”] 
Output : [‘gfg love’, ‘gfg CS’, ‘best love’, ‘best CS’] 
Explanation : All strings are coupled with one another. 
 

Method #1 : Using list comprehension

In this, we form pairs with each using list comprehension and then perform task of concatenation using another list comprehension.



Python3




# Python3 code to demonstrate working of 
# All elements concatenation across lists
# Using list comprehension
  
# initializing lists
test_list1 = ["gfg", "is", "best"]
test_list2 = ["love", "CS"]
  
# printing original lists
print("The original list 1 is : " + str(test_list1))
print("The original list 2 is : " + str(test_list2))
  
# forming pairs
temp = [(a, b) for a in test_list1 for b in test_list2]
  
# performing concatenation
res = [x + ' ' + y for (x, y) in temp]
  
# printing result 
print("The paired combinations : " + str(res))

Output:

The original list 1 is : [‘gfg’, ‘is’, ‘best’]
The original list 2 is : [‘love’, ‘CS’]
The paired combinations : [‘gfg love’, ‘gfg CS’, ‘is love’, ‘is CS’, ‘best love’, ‘best CS’]

Method #2 : Using product() + list comprehension

In this, we perform task of forming combination using product() and list comprehension performs task of concatenation.

Python3




# Python3 code to demonstrate working of 
# All elements concatenation across lists
# Using product() + list comprehension
from itertools import product
  
# initializing lists
test_list1 = ["gfg", "is", "best"]
test_list2 = ["love", "CS"]
  
# printing original lists
print("The original list 1 is : " + str(test_list1))
print("The original list 2 is : " + str(test_list2))
  
# concatenation using formatting and pairing using product
res = ['%s %s' % (ele[0], ele[1]) for ele in product(test_list1, test_list2)]
  
# printing result 
print("The paired combinations : " + str(res))

Output:

The original list 1 is : [‘gfg’, ‘is’, ‘best’]
The original list 2 is : [‘love’, ‘CS’]
The paired combinations : [‘gfg love’, ‘gfg CS’, ‘is love’, ‘is CS’, ‘best love’, ‘best CS’]

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