How to read a nested list from a file?

Question

I'm trying to read a nested list from file but with no success.

The list looks like this:

[14,[["sss","aaa"],"21a"],[[[2,3],"eee"],2423]]

When I read it from file I know that I need to split it, but am not sure which delimiter to use.

If I debug it for list from file and same list which is being assigned to during the compile time:

with open('data.txt', 'r') as f:
      list_file = f.read().split(",[")

list_original = [14,[["sss","aaa"],"21a"],[[[2,3],"eee"],2423]]

I'm getting the following results (debug):

This looks like `json` - just use `json.load` against the filehandle to convert it to a python list. — match, Jan 31 '22 at 17:00
`import json with open('data.txt', 'r') as f: res = json.loads(f.read())` — Jacques Gaudin, Jan 31 '22 at 17:03
Note: if you are serializing Python objects, why not consider [`pickle`](https://docs.python.org/3/library/pickle.html)? — Jacques Gaudin, Jan 31 '22 at 17:04
@JacquesGaudin Yes, could you refer to examples of pickle code that read a file which has nested list? I tried with open('my_data') as f: print pickle.load(f), unfortunately, got errors. — Karl 17302, Dec 19 '22 at 15:20
@user17302 it would probably be best to ask another question with the error message. — Jacques Gaudin, Dec 20 '22 at 21:54

score 3 · Accepted Answer · answered Jan 31 '22 at 17:30

3

You'll find the json module very useful for this case as follows:

import json

with open('data.txt', encoding='utf-8') as f:
    j = json.load(f)
    print(j)

Output:

[14, [['sss', 'aaa'], '21a'], [[[2, 3], 'eee'], 2423]]

answered Jan 31 '22 at 17:30

DarkKnight

1 Answers1