Marie BrunelNumpy array
initialisation
array = np.zeros((4,4))mask
# mask when value = 0
data = ma.masked_where(data == 0, data)
#test if masked value
np.ma.is_masked()divide two array
a = np.array([-1, 0, 1, 2, 3], dtype=float)
b = np.array([ 0, 0, 0, 2, 2], dtype=float)
# If you don't pass `out` the indices where (b == 0) will be uninitialized!
c = np.divide(a, b, out=np.zeros_like(a), where=b!=0)
[0. 0. 0. 1. 1.5]isnan
np.isnan()