Vertical Concatenation in Matrix in Python

When it is required to concatenate a matrix vertically, the list comprehension can be used.

Below is a demonstration of the same −

Example

 Live Demo

from itertools import zip_longest

my_list = [["Hi", "Rob"], ["how", "are"], ["you"]]

print("The list is : ")
print(my_list)

my_result = ["".join(elem) for elem in zip_longest(*my_list, fillvalue ="")]

print("The list after concatenating the column is : ")
print(my_result)

Output

The list is :
[['Hi', 'Rob'], ['how', 'are'], ['you']]
The list after concatenating the column is :
['Hihowyou', 'Robare']

Explanation

• The required packages are imported.

• A list of list is defined, and is displayed on the console.

• The list comprehension is used to zip the elements, and join them by eliminating the empty spaces.

• This is assigned to a variable.

• This variable is displayed as output on the console.