Delete array from 2D array

Question

I have a 2D array like this:

 [array([71, 35, 44,  0])
 array([56, 55,  0])
 array([32, 90, 11])
 array([ 0,  3, 81,  9, 20])
 array([0, 0]) array([0, 0]) array([0, 0]) array([ 5, 89])]

and I want to remove [0, 0]

I try to

myarray = np.delete(myarray, np.where(myarray == [0, 0]), axis=0)

but it doesnt work.

How can I remove [0, 0] ?

Are you wanting to remove all elements from your list of arrays that are equal to array([0, 0])? — James
– James, Commented Sep 9, 2018 at 0:51
That's not a 2d array. It's a 1d array of objects (pointers), which happen to be arrays of varying length. You might has well think of it as a list of arrays. — hpaulj
– hpaulj, Commented Sep 9, 2018 at 2:35

user3483203 · Accepted Answer · 2018-09-09 01:00:06Z

3

Use a list comprehension with np.array_equal:

>>> [i for i in arr if not np.array_equal(i, [0,0])]

[array([71, 35, 44,  0]),
 array([56, 55,  0]),
 array([32, 90, 11]),
 array([ 0,  3, 81,  9, 20]),
 array([ 5, 89])]

However, it is best to not work with jagged numpy arrays, as numpy does not behave well with such arrays.

edited Sep 9, 2018 at 1:00

answered Sep 9, 2018 at 0:54

user3483203

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2 Comments

Antonis Over a year ago

I store them like this: np.array([np.array([1, 2, 3]), np.array([4, 5])]). I thought this would make an array of arrays of numpy type

user3483203 Over a year ago

Numpy doesn't handle jagged arrays either.

Mohsen Hrt · Accepted Answer · 2020-04-06 02:26:22Z

1

If you have numpy array to delete first row of a 2d array: insert axis=0 to remove rows and axis=1 to remove columns

array2d=np.delete(array2d, 0, axis=0)

edited Apr 6, 2020 at 2:26

answered Apr 5, 2020 at 18:28

Mohsen Hrt

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