Python – Vertical Concatenation in Matrix
Given a String Matrix, perform column-wise concatenation of strings, handling variable lists lengths.
Input : [[“Gfg”, “good”], [“is”, “for”]]
Output : [‘Gfgis’, ‘goodfor’]
Explanation : Column wise concatenated Strings, “Gfg” concatenated with “is”, and so on.Input : [[“Gfg”, “good”, “geeks”], [“is”, “for”, “best”]]
Output : [‘Gfgis’, ‘goodfor’, “geeksbest”]
Explanation : Column wise concatenated Strings, “Gfg” concatenated with “is”, and so on.
Method #1 : Using loop
This is brute way in which this task can be performed. In this, we iterate for all the columns and perform concatenation.
Python3
# Python3 code to demonstrate working of # Vertical Concatenation in Matrix# Using loop # initializing liststest_list = [["Gfg", "good"], ["is", "for"], ["Best"]] # printing original listprint("The original list : " + str(test_list)) # using loop for iterationres = []N = 0while N != len(test_list): temp = '' for idx in test_list: # checking for valid index / column try: temp = temp + idx[N] except IndexError: pass res.append(temp) N = N + 1 res = [ele for ele in res if ele] # printing result print("List after column Concatenation : " + str(res)) |
The original list : [['Gfg', 'good'], ['is', 'for'], ['Best']] List after column Concatenation : ['GfgisBest', 'goodfor']
Method #2 : Using join() + list comprehension + zip_longest()
The combination of above functions can be used to solve this problem. In this, we handle the null index values using zip_longest, and join() is used to perform task of concatenation. The list comprehension drives one-liner logic.
Python3
# Python3 code to demonstrate working of # Vertical Concatenation in Matrix# Using join() + list comprehension + zip_longest()from itertools import zip_longest # initializing liststest_list = [["Gfg", "good"], ["is", "for"], ["Best"]] # printing original listprint("The original list : " + str(test_list)) # using join to concaternate, zip_longest filling values using # "fill"res = ["".join(ele) for ele in zip_longest(*test_list, fillvalue ="")] # printing result print("List after column Concatenation : " + str(res)) |
The original list : [['Gfg', 'good'], ['is', 'for'], ['Best']] List after column Concatenation : ['GfgisBest', 'goodfor']
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