Python | Consecutive elements pairing in list

Sometimes, while working with lists, we need to pair up the like elements in list and then store them as lists of list. This particular task has its utility in many domains, be it web development or day-day programming. Let’s discuss certain ways in which this can be achieved.

Method #1 : Using list comprehension
The list comprehension can be easily used to perform this particular task, but consecutively making the pairs of i’th and (i+1)th element.

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# Python3 code to demonstrate
# consecutive element pairing 
# using list comprehension
  
# initializing list
test_list = [5, 4, 1, 3, 2]
  
# printing original list
print("The original list : " + str(test_list))
  
# using list comprehension
# consecutive element pairing 
res = [[test_list[i], test_list[i + 1]]
        for i in range(len(test_list) - 1)]
  
# print result
print("The consecutive element paired list is : " + str(res))

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Output :



    
The original list : [5, 4, 1, 3, 2]
The consecutive element paired list is : [[5, 4], [4, 1], [1, 3], [3, 2]]

 

Method #2 : Using zip() + map()
This task can also be achieved using the zip function which performs the task for all the elements and map function does the task of pairing of consecutive elements.

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# Python3 code to demonstrate
# consecutive element pairing 
# using zip() + map()
  
# initializing list
test_list = [5, 4, 1, 3, 2]
  
# printing original list
print("The original list : " + str(test_list))
  
# using zip() + map()
# consecutive element pairing 
res = list(map(list, zip(test_list, test_list[1:])))
  
# print result
print("The consecutive element paired list is : " + str(res))

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Output :

    
The original list : [5, 4, 1, 3, 2]
The consecutive element paired list is : [[5, 4], [4, 1], [1, 3], [3, 2]]


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