[Numpy-discussion] counting non-zero entries in an ndarray

[Ian Stokes-Rees]

What is the most efficient way to do the Matlab equivalent of nnz(M)
(nnz = number-of-non-zeros function)?

I've tried Google, but no luck.

My assumption is that something like

a != 0

will be used, but I'm not sure then how to "count" the number of "True"
entries.

TIA.

Ian
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