CODEWITHSUNDEEP
pythonarraysnumpymatrix
Thomas Britton
Thomas Britton

Reputation: 123

Convert multidimesnional matrix to a one dimensional vector

I have an MxN numpy matrix and would like to make it into a one dimensional vector that just stacks each row after another. Essentially something like this...

[x11, x12 ... x1m
 x21, x22 ... x2m
 .
 .
 xn1, xn2 ... xnm]

Goes to this...

[x11, x12 ... x1m, x21, x22 ... x2m ... xn1, xn2 ... xnm]

What is the best/ most efficient way to do this?

Upvotes: 1

Views: 157

Answers (2)

Curt F.
Curt F.

Reputation: 4824

You could also .reshape(), although this method demands that you know the destination shape (for at least all but one axis) of your output array.

>>> import numpy as np
>>> foo = np.array([[1, 2, 3], [4, 5, 6]])
>>> foo.reshape(1, 6)
array([[1, 2, 3, 4, 5, 6]])

compare to:

>>> foo.reshape(-1, 1)
array([[1],
       [2],
       [3],
       [4],
       [5],
       [6]])

Upvotes: 0

Lawrence Benson
Lawrence Benson

Reputation: 1406

You could you .ravel
From the docs:

>>> x = np.array([[1, 2, 3], [4, 5, 6]]) 
>>> print np.ravel(x)
[1 2 3 4 5 6]

Upvotes: 4

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