flatten a list of variable length arrays

Question

how to convert this:

[2, 4, array([ 3.]), array([ 4.]), array([ 5.,  4.])]

to

[2,4,3,4,5,4]

I’ve tried searching but the solutions work for

[array([ 2.]), array([ 4.]), array([ 3.]), array([ 4.]), array([ 5.,  4.])]

and

[[2],[4],[3],[4],[5,4]]

Asked By: Sajid

||

Source

Answer 1

import itertools
import numpy as np

a = [2, 4, array([ 3.]), array([ 4.]), array([ 5.,  4.])]
list(itertools.chain.from_iterable(np.asarray(b).ravel() for b in a))

Answered By: Michael J. Barber

Answer 2

I like to use sum for flattening things. In your case, you want to convert the arrays to lists and the numbers to lists of numbers, first. Thus if the array is in a:

sum((list(x) if hasattr(x, '__iter__') else [x] for x in a), [])

Answered By: Gurgeh

flatten a list of variable length arrays

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