Numpy matrix to array

Question

I am using numpy  I have a matrix with 1 column and N rows and I want to get an array from with N elements   For example  if i have M   matrix   1    2    3    4     I want to get A   array  1 2 3 4     To achieve it  I use A   np array M T  0   Does anyone know a more elegant way to get the same result   Thanks

User · Answer

This will convert the matrix into array   A   np ravel M  T

User · Answer

ravel   and flatten   functions from numpy are two techniques that I would try here  I will like to add to the posts made by Joe  Siraj  bubble and Kevad   Ravel   A   M ravel   print A  A shape  gt  gt  gt   1 2 3 4   4     Flatten   M   np array   1    2    3    4    A   M flatten   print A  A shape  gt  gt  gt   1 2 3 4   4     numpy ravel   is faster  since it is a library level function which does not make any copy of the array  However  any change in array A will carry itself over to the original array M if you are using numpy ravel     numpy flatten   is slower than numpy ravel    But if you are using numpy flatten   to create A  then changes in A will not get carried over to the original array M   numpy squeeze   and M reshape -1  are slower than numpy flatten   and numpy ravel      timeit M ravel    gt  gt  gt  1000000 loops  best of 3  309 ns per loop   timeit M flatten    gt  gt  gt  1000000 loops  best of 3  650 ns per loop   timeit M reshape -1   gt  gt  gt  1000000 loops  best of 3  755 ns per loop   timeit np squeeze M   gt  gt  gt  1000000 loops  best of 3  886 ns per loop

User · Answer

Or you could try to avoid some temps with  A   M view np ndarray  A shape   -1

User · Answer

A    np array M T    depends what you mean by elegance i suppose but thats what i would do

User · Answer

result   M A1   https   docs scipy org doc numpy-1 14 0 reference generated numpy matrix A1 html  matrix A1 1-d base array

User · Answer

First  Mv   numpy asarray M T   which gives you a 4x1 but 2D array   Then  perform A   Mv 0     which gives you what you want  You could put them together  as numpy asarray M T  0

User · Answer

You can try the following variant   result np array M  flatten

User · Answer

If you d like something a bit more readable  you can do this   A   np squeeze np asarray M     Equivalently  you could also do  A   np asarray M  reshape -1   but that s a bit less easy to read

User · Answer

np array M  ravel     If you care for speed  But if you care for memory   np asarray M  ravel

[python] Numpy matrix to array

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