How to convert array objects to just elements without the [] wrapper in python?

Question

I have encountered a problem in my code where I have to pass a 2D array to a function. The function works normally when I pass the values as [[166, 1692], [463, 1506], [113, 1572], [490, 1480]], but what I am receiving from another piece of code is this: [array([498]), array([1568])], [array([242]), array([1688])]]. I want to convert this format to the previous one. I want then in x,y format and I have tried many ways to convert back and forth and it does not work. I have to remove that "array" wrapper and also the "[]" wrapper around every element. Is there any way to do this? Any help will be much appreciated. Thank you.

UPDATE: Thank you for all the answers. The answer by Ayoub Zarou works as expected. Thank you once again.

According to the documentation you can use .tolist() to convert your array to a list. — CMMCD
– CMMCD, Commented Aug 1, 2019 at 13:05

Axois · Accepted Answer · 2019-08-01 13:13:21Z

3

I am assuming you are dealing with numpy arrays, "yourlist".tolist() should do the trick.

import numpy as np

a = np.array([[1, 2], [3, 4]])
a = list(a)
print(a)
# outputs [array([1, 2]), array([3, 4])]

print(np.array(a).tolist())
# outputs [[1, 2], [3, 4]]

# If you are removing the brackets, you can simply flatten() it.
a = np.array(a).flatten()
print(a.tolist())
# outputs [1, 2, 3, 4]

edited Aug 1, 2019 at 13:13

answered Aug 1, 2019 at 13:04

Axois

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planet_pluto Over a year ago

Thanks for the explanation and telling where I am going wrong.

Ayoub ZAROU · Accepted Answer · 2019-08-01 13:09:14Z

0

try doing :

np.array(x).reshape((len(x), -1)).tolist()

where x is your list

answered Aug 1, 2019 at 13:09

Ayoub ZAROU

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Ayoub ZAROU Over a year ago

Happy coding , you could approve the answer if it was helpful

Victor Ruiz · Accepted Answer · 2019-08-01 13:10:33Z

0

Maybe this helps:

from numpy import array
a = [array([498]), array([1568]), array([242]), array([1688])]
b = array(a).tolist()
print(b)

Output is:

[[498], [1568], [242], [1688]]

Another solution which gives the same output:

import numpy as np
a = [array([498]), array([1568]), array([242]), array([1688])]
b = list(map(np.ndarray.tolist, a))

answered Aug 1, 2019 at 13:10

Victor Ruiz

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Comments

Justus · Accepted Answer · 2019-08-01 13:22:57Z

0

You can pick the first value out of each array with a list comprehension:

from numpy import array    
inlist = [[array([1]), array([2])], [array([3]), array([4])], [array([5]), array([6])]]
# form of inlist: [[array([1]), array([2])], [array([3]), array([4])], [array([5]), array([6])]]
outlist = [[a[0], b[0]] for a,b in inlist]

Which gives you

[[1, 2], [3, 4], [5, 6]]

answered Aug 1, 2019 at 13:22

Justus

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