How do I remove all zero elements from a NumPy array?

Question

I have a rank-1 numpy.array of which I want to make a boxplot. However, I want to exclude all values equal to zero in the array. Currently, I solved this by loo

Answer 1

This is a case where you want to use masked arrays, it keeps the shape of your array and it is automatically recognized by all numpy and matplotlib functions.

X = np.random.randn(1e3, 5)
X[np.abs(X)< .1]= 0 # some zeros
X = np.ma.masked_equal(X,0)
plt.boxplot(X) #masked values are not plotted

#other functionalities of masked arrays
X.compressed() # get normal array with masked values removed
X.mask # get a boolean array of the mask
X.mean() # it automatically discards masked values