how to add number at the end of row in array numpy python

Question

Is any function that let me to add any number (e.g. "0") at end of every row in array. Example: I have two dimensional array:

ar=[[0,0,1],
[1,1,1],
[0,1,0]]

And I want add it to other 1-dimensional array, so I have:

 otherarray=numpy.array([],dtype=bool)
    otherarray=np.append(otherarray, ar)

Result:

 otherarray=[0,0,1,1,1,1,0,1,0]

And it works. But I need to add to every row of ar any number, e.g. 0 and get it as a result in otherarray (not modifying ar). Result I want:

[0,0,1,0,1,1,1,0,0,1,0,0]

I am doing it using for loop (I'm putting every element to otherarray one-by-one) but now I'm asking: is any better way?

akuiper · Accepted Answer · 2017-04-05 15:36:02Z

1

You can append a zero column to ar and then flatten it:

A = np.array(ar)    

np.hstack([A, np.zeros((A.shape[0], 1), dtype=A.dtype)]).ravel()
# array([0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0])

answered Apr 5, 2017 at 15:36

akuiper

216k33 gold badges362 silver badges379 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Great idea! Thanks!