如何合并Python列表中包含的数组

Question

If I have something like;

a=np.array([1,2])
b=np.array([1,4])
c=[]

Firstly, what is the built in python function to enable the combination of a and b so that we have array([1,2],[1,4])

Also another question just for future reference, in the past ended up with things like [array([1,2]), array([1,4])] I wasn't sure what to do so I just had to redo the code. Is it bad practise to end up with a result like this or is there a function which can change this to array([1,2],[1,4]) ?

Thank you.

Answer 1

See numpy vstack function:

>>> import numpy as np
>>> a = np.array([1, 2])
>>> b = np.array([3, 4])
>>> np.vstack((a, b))
array([[1, 2],
       [3, 4]])

Answer 2

You might want to look into np.concatenate

>>> a = np.array([[1, 2], [3, 4]])
>>> b = np.array([[5, 6]])
>>> np.concatenate((a, b), axis=0)
array([[1, 2],
       [3, 4],
       [5, 6]])

http://docs.scipy.org/doc/numpy/reference/generated/numpy.concatenate.html