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Python – Summation of kth column in a matrix
• Last Updated : 11 Dec, 2019

Sometimes, while working with Python Matrix, we may have a problem in which we require to find the summation of a particular column. This can have a possible application in day-day programming and competitive programming. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using `sum() + zip()`
This task can be solved using the combination of above functions. In this, we pass in the zip() the list, to access all columns and sum() to get summation of columns.

 `# Python3 code to demonstrate working of``# Matrix Kth column summation``# using sum() + zip()`` ` `# initialize list``test_list ``=` `[[``5``, ``6``, ``7``],``            ``[``9``, ``10``, ``2``], ``            ``[``10``, ``3``, ``4``]]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initialize K``K ``=` `2`` ` `# Matrix Kth column summation``# using sum() + zip()``res ``=` `[``sum``(idx) ``for` `idx ``in` `zip``(``*``test_list)][K] `` ` `# printing result``print``(``"Sum of Kth column is : "` `+` `str``(res))`
Output :
```The original list is : [[5, 6, 7], [9, 10, 2], [10, 3, 4]]
Sum of Kth column is : 13
```

Method #2 : Using loop
This is brute force way to solve this problem. In this, we iterate through the matrix and take summation of column by testing column number.

 `# Python3 code to demonstrate working of``# Matrix Kth column summation``# Using loop`` ` `# initialize list``test_list ``=` `[[``5``, ``6``, ``7``],``            ``[``9``, ``10``, ``2``], ``            ``[``10``, ``3``, ``4``]]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initialize K``K ``=` `2`` ` `# Matrix Kth column summation``# Using loop``res ``=` `0``for` `sub ``in` `test_list:``    ``for` `idx ``in` `range``(``0``, ``len``(sub)):``        ``if` `idx ``=``=` `K:``            ``res ``=` `res ``+` `sub[idx]`` ` `# printing result``print``(``"Sum of Kth column is : "` `+` `str``(res))`
Output :
```The original list is : [[5, 6, 7], [9, 10, 2], [10, 3, 4]]
Sum of Kth column is : 13
```

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