How to get a data structure from inside a string (Python)

Question

I have a program which outputs a list in a .txt file on a server and I want to save that list in a new variable.
I'm doing:

with open ("file.txt", "r") as myfile:
    data = myfile.read().replace('\n', '')
var = data

but obviously print(var) returns a string "[list, of, stuff]"

Yeah I can bypass the txt-save procedure but what in case I could not?

Does this answer your question? [How to convert string representation of list to a list?](https://stackoverflow.com/questions/1894269/how-to-convert-string-representation-of-list-to-a-list) — AMC, Sep 26 '20 at 21:46

score 6 · Accepted Answer · edited Jul 19 '14 at 07:58

you can use AST

import ast
var="[list, of, stuff]"
var=ast.literal_eval(var)
print var[0]
#output list

From docs

ast.literal_eval(node_or_string) Safely evaluate an expression node or a string containing a Python expression. The string or node provided may only consist of the following Python literal structures: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, and None.

If you're original data was serialized using JSON then you could also use the json module from the Python standard library.

Even if it was just print(some_list) you could still use the json library; i.e:

>>> from json import dumps, loads
>>> xs = [1, 2, 3]
>>> loads(dumps(xs)) == loads(repr(xs))
True

ast.literal_eval() solved my problem perfectly. Thanks! – Leonardo Romanello Jul 19 '14 at 08:14 — Leonardo Romanello, Jul 19 '14 at 08:14

How to get a data structure from inside a string (Python)

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