CODEWITHSUNDEEP
pythonnumpy
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Reputation: 29099

numpy: is there an `allclose(np.array, scalar)`?

In numpy you can use the allclose(X, Y) function to check element-wise for approximate equality between two arrays. Moreover, with an expression like X==5 you can check element-wise equality between an array and a scalar.

Is there a function that combines both functionalities?? That is, can compare an array and a scalar for approximate element-wise equality??

Upvotes: 3

Views: 2120

Answers (1)

MSeifert
MSeifert

Reputation: 152725

The term array or array-like in the numpy documentation mostly indicates that the input is converted to an array with np.asarray(in_arg) or np.asanyarray(in_arg). So if you input a scalar it will be converted to an scalar array:

>>> import numpy as np
>>> np.asarray(5)    # or np.asanyarray
array(5)

And the functions np.allclose or np.isclose just do element-wise comparison no matter if the second argument is a scalar array, an array with the same shape or an array that correctly broadcasts to the first array:

>>> import numpy as np
>>> arr = np.array([1,2,1,0,1.00001,0.9999999])
>>> np.allclose(arr, 1)
False
>>> np.isclose(arr, 1)
array([ True, False,  True, False,  True,  True], dtype=bool)

>>> np.isclose(arr, np.ones((10, 6)))
array([[ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True],
       [ True, False,  True, False,  True,  True]], dtype=bool)

So no need to find another function that explicitly handles scalars, these functions already correctly work with scalars.

Upvotes: 2

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