a simple way to editing elements in a 2D array Python:

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I would like to be able to perform operations on specific elements in a 2D array, if it meets a criterion. in the below example the code makes any value < 0.5 = 0.

Does anyone know of a simple way of doing this? Below is my code, but im sure there is a simpler way.

import numpy as np

x = 5
y = 5

x3 = np.random.rand(x,y)

def choice(arr):
    row = -1
    column = -1
    for i in arr:
        row += 1
        for j in i:
            column += 1
            if j >= 0.5:
                arr[row,column] = j
            else:
                arr[row,column] = 0
                
            if column == y - 1:
                column = -1
    
    return arr

y3 = choice(x3.copy())
data-science data-analysis numpy arrays python
2 Answers

To zero all the indices that are < 0.5,

>>> x3 = np.random.rand(5, 5)
>>> x3
array([[0.50866152, 0.56821455, 0.88531855, 0.36596337, 0.08705278],
       [0.96215686, 0.19553668, 0.15948972, 0.20486815, 0.74759719],
       [0.36269356, 0.54718917, 0.66196524, 0.82380099, 0.77739482],
       [0.0431448 , 0.47664036, 0.80188153, 0.8099637 , 0.65258638],
       [0.84862179, 0.22976325, 0.03508076, 0.72360136, 0.76835819]])
>>> x3[x3 < .5] = 0
>>> x3
array([[0.50866152, 0.56821455, 0.88531855, 0.        , 0.        ],
       [0.96215686, 0.        , 0.        , 0.        , 0.74759719],
       [0.        , 0.54718917, 0.66196524, 0.82380099, 0.77739482],
       [0.        , 0.        , 0.80188153, 0.8099637 , 0.65258638],
       [0.84862179, 0.        , 0.        , 0.72360136, 0.76835819]])
AKX_516850

Just for enumerate and ternary condition introduction you can do :

import numpy as np

x = 5
y = 5

x3 = np.random.rand(x,y)

def choice(arr):
    for row_idx, row in enumerate(arr):
        for col_idx, val in enumerate(row) :
            arr[row_idx,col_idx] = val if val >= 0.5 else 0
    return arr

y3 = choice(x3.copy())

But AKX solution is just better.

user_80807580
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