Member Avatar for psichoman5

I dont know how to convert a matrix of 10x10 into 4 matrices of 5x5, for example:

[[10, 11, 12, 13, 14, 15, 16, 17, 18, 19], # matrix 10x10
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49],
 [50, 51, 52, 53, 54, 55, 56, 57, 58, 59],
 [60, 61, 62, 63, 64, 65, 66, 67, 68, 69],
 [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]]

I need to convert into this:

[[10, 11, 12, 13, 14] # 4 like this with the other numbers too
 [20, 21, 22, 23, 24] 
 [30, 31, 32, 33, 34]
 [40, 41, 42, 43, 44]
 [50, 51, 52, 53, 54]]

Thanks!

  • 2 Contributors
  • 2 Replies
  • 257 Views
  • 1 Hour Discussion Span
  • Latest Post Latest Post by vegaseat
Member Avatar for vegaseat

One of the ways would be to use slicing ...

''' matrix_slice101.py
slice a 5x5 matrix out of a 10x10 matrix
'''

# matrix 10x10
matrix10x10 = \
[[10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49],
 [50, 51, 52, 53, 54, 55, 56, 57, 58, 59],
 [60, 61, 62, 63, 64, 65, 66, 67, 68, 69],
 [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]]

matrix5x5 = []
# use slicing [:5] to get first 5 rows
for row in matrix10x10[:5]:
    # use slicing [:5] to get first 5 elements in each row
    matrix5x5.append(row[:5])

# check result
import pprint
pprint.pprint(matrix5x5)

'''result ...
[[10, 11, 12, 13, 14],
 [20, 21, 22, 23, 24],
 [30, 31, 32, 33, 34],
 [40, 41, 42, 43, 44],
 [50, 51, 52, 53, 54]]
'''
Member Avatar for vegaseat

The above can be simplified to ...

matrix10x10 = \
[[10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49],
 [50, 51, 52, 53, 54, 55, 56, 57, 58, 59],
 [60, 61, 62, 63, 64, 65, 66, 67, 68, 69],
 [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
 [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
 [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
 [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]]

matrix5x5 = [row[:5] for row in matrix10x10[:5]]
Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.