This question consists of use of list comprehension in python.

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row_num = int(input("Input number of rows: "))
col_num = int(input("Input number of columns: "))
multi_list = [[0 for col in range(col_num)] for row in range(row_num)]

for row in range(row_num):
    for col in range(col_num):
        multi_list[row][col]= row*col

print(multi_list)

doubt:
I didn't understand line 3 of the above code.

What I have tried:

This question consists of use of list comprehension in Python.I cannot understand line 3.Kindly help.

Posted 28-Jul-20 21:59pm

Saksam2020

Updated 28-Jul-20 22:37pm

CPallini

v2

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OriginalGriff · Answer 1 · 2020-07-28T22:08:00

Solution 1

It's just declaring a 2d List.
See here: Two-dimensional lists (arrays) - Learn Python 3 - Snakify[^]

Posted 28-Jul-20 22:08pm

OriginalGriff

Comments

CPallini 29-Jul-20 4:38am

5.

Sandeep Mewara · Answer 2 · 2020-07-28T22:29:00

Quote:
multi_list = [[0 for col in range(col_num)] for row in range(row_num)]

col_num = 3
for col in range(col_num)

=> for loop from 0 to 3 (0,1,2)

row_num = 4
for row in range(row_num)

=> for loop from 0 to 4 (0,1,2,3)

[0 for row in range(4)]

=> [0, 0, 0, 0]

Thus,

multi_list = [[0 for col in range(col_num)] for row in range(row_num)]

=> [[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]

OR (for easier read)
[[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0]]

Defines a matrix of 4*3 with that line.

Richard MacCutchan · Answer 3 · 2020-07-28T22:34:00

Solution 3

See 5. Data Structures — Python 3.7.8 documentation[^].

Posted 28-Jul-20 22:34pm

Richard MacCutchan