How to extract data from list stored as a string like a list?

Question

I have coordinates as keys in dict and want to read them like a normal list when I try to extract them. See example:

testlist = {'[0, 0]': 0, '[1 ,1]': 1}

for tmp in testlist:
   if testlist[tmp] == 1:
      print(tmp[0], tmp[1])

The above example should return

1 1

However it outputs

[ 1

I tried list(tmp) and tmp.split() but neither gave the desired output. There probably exists an easy solution, but I could not find it yet.

score 3 · Accepted Answer · answered Sep 02 '23 at 00:05

3

You can use ast.literal_eval to evaluate the strings when needed, converting them to lists. For example:

import ast

testlist = {'[0, 0]': 0, '[1 ,1]': 1}

for key in testlist:
    if testlist[key] == 1:
        tmp = ast.literal_eval(key)
        print(tmp[0], tmp[1])

This produces the desired result:

1 1

Note that ast.literal_eval is a restricted form of eval that is safe from harmful side effects.

answered Sep 02 '23 at 00:05

Tom Karzes

22,815
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1

In this specific case, `json.loads()` might be better. – John Gordon Sep 02 '23 at 00:08
1

@JohnGordon It depends on where the data is coming from and what other forms it might take. If it's just two-element lists of integers, then `ast.literal_eval` is perfectly fine. – Tom Karzes Sep 02 '23 at 00:11

Coder · Answer 2 · 2023-09-02T00:14:25.270

0

This works without imports:

testlist = {'[0, 0]': 0, '[1 ,1]': 1}

for tmp in testlist:
   if testlist[tmp] == 1:
        test = list(tmp.replace("[", "").replace("]", "").replace(",", "").split())
        print(int(test[0]), int(test[1]))

But there're definitely better solutions lol

edited Sep 02 '23 at 00:14

answered Sep 02 '23 at 00:06

Coder

75
6

How to extract data from list stored as a string like a list?

2 Answers2