CODEWITHSUNDEEP
pythonnumpy
maratreus
maratreus

Reputation: 3

How to create an array of arrays and how to reffer to an element using numpy

I am trying to recreate the game of life as an exercise but I don't know how to create the matrix and refer to the elements.

I tried this but it just create a array

for col in range(0,width):
for row in range(0,height):
    at = np.append(at, 1 if rnd.random() < 0.2 else 0)
array = np.append(a, at)
array_temp = np.array([])

Upvotes: 0

Views: 34

Answers (3)

K.Mat
K.Mat

Reputation: 1649

You can vectorize the randomization function and apply it to empty matrix:

import random
import numpy as np

def f(i):
    return 1 if random.random() < 0.2 else 0
    
width = 5
height = 5
result = np.vectorize(f)(np.empty([width, height]))
print(result)

Upvotes: 0

Andrew Eckart
Andrew Eckart

Reputation: 1726

An alternate NumPy solution:

>>> import numpy as np
>>> seed = np.random.random((10,5))
>>> seed
array([[0.43419963, 0.12927612, 0.47783417, 0.6698047 , 0.43966626],
       [0.56238954, 0.90856671, 0.84653548, 0.54566383, 0.98273554],
       [0.13319855, 0.14511374, 0.44135731, 0.57732303, 0.63272811],
       [0.67107476, 0.113417  , 0.25593979, 0.67509295, 0.35349618],
       [0.86125898, 0.21895507, 0.46389417, 0.18839496, 0.90046474],
       [0.03403771, 0.19303373, 0.02871153, 0.85036184, 0.95387585],
       [0.3316397 , 0.84540023, 0.97718179, 0.95335886, 0.9703442 ],
       [0.0221273 , 0.7636946 , 0.45536691, 0.64732677, 0.57123722],
       [0.40939072, 0.49219486, 0.90310105, 0.12079284, 0.41212587],
       [0.26332532, 0.52836011, 0.45873454, 0.69026349, 0.72141677]])
>>> board = np.where(seed < 0.2, 1, 0)
>>> board
array([[0, 1, 0, 0, 0],
       [0, 0, 0, 0, 0],
       [1, 1, 0, 0, 0],
       [0, 1, 0, 0, 0],
       [0, 0, 0, 1, 0],
       [1, 1, 1, 0, 0],
       [0, 0, 0, 0, 0],
       [1, 0, 0, 0, 0],
       [0, 0, 0, 1, 0],
       [0, 0, 0, 0, 0]])

Upvotes: 1

Mark
Mark

Reputation: 92450

You can avoid the loop and make a weighted Numpy matrix using numpy.random.choice

import numpy as np

width = 5
height = 4
np.random.choice(2, [height, width], p=[0.8, .2])

Gives you something like:

array([[1, 0, 1, 0, 0],
       [0, 1, 0, 1, 0],
       [0, 1, 0, 1, 1],
       [0, 0, 0, 0, 0]])

Upvotes: 0

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