Numpy Matrix not flattening

Question

I am trying a flatten a Numpy array but flatten, ravel, and hstack are not doing it. I need to be able to create a Pandas series from the array, but I can't seem to get it flat for Pandas to accept:

print(type(centroids))
# <class 'numpy.matrix'>

print(centroids.shape)
# (5, 9328)

centroid = centroids[i]
centroid = np.hstack(centroid)

print(centroid)
# [[ 0.98487911  0.7483803  11.80978353 ...  0.97687837  0.21988038
   3.33842549]]  <-- still enclosed by two brackets

print(centroid.shape)
# (1, 9328)

centroid = pd.Series(centroid, name='value') <-- throws exception: Exception: Data must be 1-dimensional

Does this answer your question? [How to make a flat list out of list of lists?](https://stackoverflow.com/questions/952914/how-to-make-a-flat-list-out-of-list-of-lists) — Kevin Welch, May 11 '20 at 18:50
@KevinWelch unfortunately no, I tried it and it didn't work. Even if it did, I'm looking for a matrix-based approach...not an iterative one. Thanks though. — Clayton C., May 11 '20 at 19:09

score 1 · Accepted Answer · answered May 11 '20 at 18:57

1

The problem is that centroid is a np.matrix, not an array. Your code will work if you simply change the last line to:

centroid = pd.Series(np.array(centroid).ravel(), name='value')

answered May 11 '20 at 18:57

Mercury

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Numpy Matrix not flattening

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