Find and replace specific value in numpy ndarray?

Question

I want to iterate through a numpy ndarray and, if any values are less than X, replace one of them with X.

I have tried doing array_name[ array_name < X] = X but this replaces all of the values that are less than X.

I can use a for loop, but I feel like there's probably a more concise way already bundled with numpy.

        for i in array_name:
            if i < X:
                i = X
                break

Is there a way to do this more elegantly?

Rikard Olsson · Accepted Answer · 2019-03-16 20:09:14Z

1

array_name < X

Returns same array but with True or False. Then you can just pick an index where the cell is True

idx = np.argwhere(array_name < X)[i]
array_name[idx] = value

Here, you can choose i arbitrarily

answered Mar 16, 2019 at 20:09

Rikard Olsson

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2 Comments

What are you doing with i there?

Any index in np.argwhere(array_name < X) satisfies your constraint. So i is one of them