Question

How to define a two-dimensional list (array) in Python

Answer 1

cols, rows = 4, 3;

matrix = [[0 for x in range(cols)] for y in range(rows)] 
  
for i in range(len(matrix)):
    for j in range(len(matrix[i])):
        print(matrix[i][j], end=' ')
    print()


  
  
'''
run:
  
0 0 0 0
0 0 0 0
0 0 0 0
  
'''

 

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Answer 2

cols, rows = 4, 3;

matrix = [[0 for x in range(cols)] for y in range(rows)] 
  
matrix[0][0] = 9
matrix[1][3] = 13
matrix[2][1] = 982

for i in range(len(matrix)):
    for j in range(len(matrix[i])):
        print(matrix[i][j], end=' ')
    print()

  
  
'''
run:
  
9 0 0 0
0 0 0 13
0 982 0 0
  
'''

 

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Answer 3

import numpy

matrix = numpy.zeros((3, 4))
  
matrix[0][0] = 9
matrix[1][3] = 13
matrix[2][1] = 982

for i in range(len(matrix)):
    for j in range(len(matrix[i])):
        print(matrix[i][j], end=' ')
    print()

  
  
'''
run:
  
9.0 0.0 0.0 0.0
0.0 0.0 0.0 13.0
0.0 982.0 0.0 0.0
  
'''

 

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