adding up columns in 2D lists in Python

Question

I'm pretty new to programming, and Python. My textbook has not given me really any information on this and I am stumped now. This is my current code, I need to display the added up columns, and display them like I have the rows.

EDIT:

I had read a few different posts here about using zip() but my book didn't cover it so I couldn't really use it. However this is what I ended up doing:

import random

ROWS = 3
COLS = 3

def main ():
    values = [[0, 0, 0],
             [0, 0, 0],
             [0, 0, 0]] 
for r in range (ROWS):
    for c in range(COLS):
        values[r][c]= random.randint(1,4)

#add up rows
    row0=sum(values[0])
    row1=sum(values[1])
    row2=sum(values[2])

#add up columns
    col0=(values[0][0]+values[1][0]+values[2][0])
    col1=(values[0][1]+values[1][1]+values[2][1])
    col2=(values[0][2]+values[1][2]+values[2][2])

#print results
    print ("List: ")
    print (values)

print ("Total of row 0 is", row0 ) 
print ("Total of row 1 is", row1)
print ("Total of row 2 is", row2 )
print ("Total of column 0 is", col0)
print ("Total of column 1 is", col1)
print ("Total of column 2 is", col2)


main()

Can you be more specific about your problem? What is your expected output? — zeeMonkeez
– zeeMonkeez, Commented Nov 21, 2015 at 0:47
Sounds like zip() is what you need. It basically swaps columns and rows for you. — Felk
– Felk, Commented Nov 21, 2015 at 0:49

Saiful Azad · Accepted Answer · 2015-11-21 02:49:50Z

1

Here I am not using list comprehension or zip as you are new to programming. Hope this code below is pretty simple and self explanatory.

for c in range(COLS):
    sum_col =0  #reset value all row after read
    for r in range (ROWS):
        sum_col+= values[r][c] # sum each element 
    print (sum_col) #finaly print it

edited Nov 21, 2015 at 2:49

answered Nov 21, 2015 at 2:30

Saiful Azad

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Comments

Ryan · Accepted Answer · 2015-11-21 02:09:02Z

0

This line of code will display a list of the columns totaled. Here is a description of the zip function.

print [sum(x) for x in zip(*values)]

answered Nov 21, 2015 at 2:09

Ryan

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