running a loop while numpy array contains no zeros

Question

I am trying to run a loop while there are no zeros in my numpy array. was wondering if there was a good way of checking array for zeros rather than going through it line by line.

Please show us some code, maybe? What's the shape of your array, for starters? What are you actually doing in the larger scheme of things? — AKX
– AKX, Commented Dec 30, 2019 at 19:40
Running a loop with numpy is usually bad design, but you need to show your code. — Alexander
– Alexander, Commented Dec 30, 2019 at 19:42

mtrw · Accepted Answer · 2019-12-30 19:45:42Z

1

You can use numpy.all:

while np.all(myarray != 0):
    dostuff

edited Dec 30, 2019 at 19:45

answered Dec 30, 2019 at 19:42

mtrw

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Inder · Accepted Answer · 2019-12-30 19:59:08Z

1

An alternative approach can be to use np.count_nonzero:

while np.count_nonzero(arr) == arr.size:
    #your code here

edited Dec 30, 2019 at 19:59

answered Dec 30, 2019 at 19:47

Inder

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4 Comments

mtrw Over a year ago

count_nonzero returns an ND array if arr has more than one dimension, so you probably need to flatten arr in the call. Also, OP wants to know if there are no zeros, so doesn't this have to be something like != len(arr)?

Inder Over a year ago

@mtrw I am sorry but I think you are mistaken here, count_nonzero always an integer, if the axis is not given, since the default value of the axis is None so it will return an integer even for a multi-dimensional array

mtrw Over a year ago

Oh, I missed that the call flattens the array internally if axis is left at None - nice.

Inder Over a year ago

@mtrw thank you for the second suggestion I think the edit fixes the condition.

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