How to extract numpy arrays from specific column in pandas frame and stack them as a single numpy array [duplicate]

Question

I have a pandas frame like this.

pd.DataFrame(data={'name':['name1','name2'],'vector':[np.array([1,2,3,4]),np.array([12,22,34,4])]})

I want to extract the vectors from the frame as a matrix like this.

np.array([[1,2,3,4],[12,22,34,4]])

plasmon360 · Accepted Answer · 2017-05-10 00:41:09Z

np.array(df['vector'].tolist())

will result in

array([[ 1, 2, 3, 4], [12, 22, 34, 4]])

or

df['vector'].as_matrix()

will result in

array([array([1, 2, 3, 4]), array([12, 22, 34, 4])], dtype=object)

Chih-Hsu Jack Lin · Accepted Answer · 2017-05-10 01:59:02Z

2

df.vector.values should be the shortest.

answered May 10, 2017 at 1:59

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2 Answers 2