How to transform python string into array

Question

a python string:

'[[4,2],[8,5]]'

for example, where you have a fairly complex multidimensional array of information, maybe is extracted from a file or user input and is naturally a string. How should I go about turning this into an actual array. I want a general implementation so that I can perform this to any multidimensional and complex array. This is for a machine learning project, and any of these arrays can be represented with a shape (e.g. (3,2,5) ) and a list of its corresponding values (e.g. [1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0] ) such that is may look like:

[[[1,2,3,4,5],
  [6,7,8,9,0]],
 [[1,2,3,4,5],
  [6,7,8,9,0]],
 [[1,2,3,4,5],
  [6,7,8,9,0]]]

You can execute code with eval e.g. a = eval('[[4,2],[8,5]]') — tomjn
– tomjn, Commented Mar 11, 2021 at 13:35
This is a duplicate question: check this. stackoverflow.com/questions/25572247/… — kabooya
– kabooya, Commented Mar 11, 2021 at 13:38
Question has actually nothing to do with machine-learning or neural-network - kindly do not spam irrelevant tags (removed). — desertnaut
– desertnaut, Commented Mar 11, 2021 at 13:46

ullas kunder · Accepted Answer · 2021-03-11 13:41:30Z

0

try this:

def flatten_list(_2d_list):
    flat_list = []
    for element in _2d_list:
        if type(element) is list:
            for item in element:
                flat_list.append(item)
        else:
            flat_list.append(element)
    return flat_list

nested_list = [[4,2],[8,5]]

print(nested_list)
print(flatten_list(nested_list))

answered Mar 11, 2021 at 13:41

ullas kunder

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3 Comments

desertnaut Over a year ago

Notice that in OP's question the list expression is actually a string; it is '[[4,2],[8,5]]', not [[4,2],[8,5]].

ullas kunder Over a year ago

ooops......then we can use string.split() method on '[[4,2],[8,5]]' to convert to string. can we?

desertnaut Over a year ago

Well, why don't you try it? :)

Alex97 · Accepted Answer · 2021-03-11 13:42:00Z

0

import numpy as np
list = [1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]
array = np.array(list)
array = np.reshape(array, (3,2,5))

answered Mar 11, 2021 at 13:42

Alex97

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