read a text file, find all integers, append to list

[deanhystad]

The file needs to look like the example posted by oldtrafford.

Output:
Text
..
..
...
..
..
*Nset, nset=PATH, unsorted
13, 721, 722, 723, 724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735
...
2559, 2560, 2561, 2562, 2563, 2564, 72
*Text
....
...
...
..
Text

I wouldn't be surprised if the starting mark should be Nset, not *Nset, and the ending mark Text, not *Text. Looking at it again I think maybe the numbers start after the Nset line and continue until there is a line that starts with text. Maybe this is a better fit:

import json
import re
 
integer_pattern = re.compile("[+-]?[0-9]+")
 
def get_numberes_from_file(filename):
    numbers = []
    with open(filename, "r") as file:
        for line in file:
            # Marks the beginning of int data
            if line.startswith("Nset"):
                break
        for line in file:
            # Read lines until encounter line without numbers
            matches = map(int, re.findall(integer_pattern, line))
            if matches:
                numbers += matches
            else:
                break
    return numbers
 
input_files = ["test.txt", "test2.txt", "test3.txt"]
numbers = {}
for filename in input_files:
    numbers[filename] = get_numberes_from_file(filename)
 
with open("output.inp", "w") as file:
    json.dump(numbers, file, indent=4)