CODEWITHSUNDEEP
pythonpython-2.7matrixsum
John Finkelstein
John Finkelstein

Reputation: 1

How to sum a row in matrix without numpy?

How do I check the sum of a row without numpy? If I have this code:

Matrix = [["X", "X", "X"],[ "O", "O", "X"], ["X", "O", "X"]]

How do I check the sum of every row in the matrix without numpy?

Example:

In the matrix above my sum would be x = "XXX", "OOX", "XOX"

EDIT

I do not like to use stuff like .join and .map.

Upvotes: 0

Views: 7068

Answers (3)

Reen
Reen

Reputation: 429

Your code doesn't create a matrix. It errors out. If you want to represent a matrix with lists, you could do the following:

matrix = [[1,1,1],[2,2,2],[0,0,0]]

You could then find the sum of each row with a list comprehension:

[sum(row) for row in matrix]

EDIT: The question has changed, so for later readers I want to make sure it's clear. sum will add numbers, not concatenate strings. If you want to concatenate strings, your list comprehension should look like this:

[[''.join(row) for row in matrix]]

If you want to assign names to each row, instead of creating a separate variable for each, stick the list of sums into a for loop and assign each sum to a dictionary:

sum_dict = {}
i=0
for s in sum_list:
    sum_dict['r'+str(i)] = s
    i +=1

Will give you a dictionary with keys r0,r1,r2, etc.

Upvotes: 1

Moses Koledoye
Moses Koledoye

Reputation: 78546

You can use a list comprehension and str.join:

Matrix = [["X", "X", "X"],[ "O", "O", "X"], ["X", "O", "X"]]
m = [''.join(i) for i in matrix]
print(m)
# ['XXX', 'OOX', 'XOX']

To create a more general solution for adding different types you can use reduce with operator.add:

from operator import add
# from functools import reduce # Py3

Matrix = [1, 1, 2], ["O", "O", "X"], ["X", "O", "X"]

m = [reduce(add, i) for i in Matrix]
print(m)
# [4, 'OOX', 'XOX']

Upvotes: 1

Ohjeah
Ohjeah

Reputation: 1307

You can use join on an empty string:

x = [''.join(row) for row in Matrix]

Upvotes: 0

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