How to connect Python arrays

Question

I don't understand when it is sum operation or just connect two arrays

x = np.arange(10)
x
#array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

x[4]=44
x
#array([ 0,  1,  2,  3, 44,  5,  6,  7,  8,  9])

xs=np.split(x,5)
xs
#[array([0, 1]), array([2, 3]), array([44,  5]), array([6, 7]), array([8, 9])]

what is this shape ?

xs=np.split(x,5)
xs
#[array([0, 1]), array([2, 3]), array([44,  5]), array([6, 7]), array([8, 9])]

i=2
xscn = np.concatenate((xs[:i]+xs[i+1:]))
xscn
#array([0, 1, 2, 3, 6, 7, 8, 9])

"so why it no summing the array just put them side side (not ariane grande ha ha ha"

f=(xs[:i]+xs[i+1:])
f

#[array([0, 1]), array([2, 3]), array([6, 7]), array([8, 9])]

so it just put one array after other.

cc=np.concatenate(f)   
cc  
#array([0, 1, 2, 3, 6, 7, 8, 9])

ff=xs[:i]+xs[i+1:]
ff
#[array([0, 1]), array([2, 3]), array([6, 7]), array([8, 9])]

so when it adds and when it just sets one list after other also I can't type the shapes.

Answer 1

1. type(np.split(x, 5)) == list , and list s don't have a shape , but you can find their len gths;

2. xs is a list , so adding two lists concatenates them:

    xs[:i]+xs[i+1:] == [array([0, 1]), array([2, 3]), array([6, 7]), array([8, 9])] 

   Then you concatenate all of these tiny arrays into one, which gives you back your original array.

3. Same reason as above
4. Same reason as above

The problem is, Python list s are not NumPy ndarray s, and behave differently.