Inconsistency in Python programming language?

[adt]

It's better to use ast.literal_eval as it is safer compared to eval

Thanks buran, for your kind suggestion. Noted for future use.

It is seen that ast.literal_eval() too, throws error in case of mixed strings.

---

If there is still an error, please give full bug report!

Test results for the latest version of func() are placed below:

import ast
import re
from tokenize import generate_tokens, NUMBER
#import io

def func(s):
    t = re.sub(r'\s+', '', s)
    sign = True
    for tok in generate_tokens(iter([t, '']).__next__):
        if sign and tok[1] in ('-', '+'):
            sign = False
            continue
        if tok[0] == NUMBER:
            return ast.literal_eval(t[:tok[3][1]])
        return 0
    return 0
     
if __name__ == '__main__':
    sample = [
        ("45", 45),
        ("4.5", 4.5),
        ("4.5ABC", 4.5),
        ("ABCD", 0),
        ("AB45", 0),
        ("   2  45  7  ", 2457),
        ("    2   4   .   5   7   ", 24.57),
        ("+4.5", 4.5),
        ("-4.5", 4.5),   # AssertionError (see Error Box)
        ]
    for inp, out in sample:
        assert out == func(inp)
        print(func(inp))

Output:
45
4.5
4.5
0
0
2457
24.57
4.5

Error For Last String "-4.5"

Error:
Traceback (most recent call last):
  File "J:\AdtPython-Practice\00-RoughTesting.py", line 92, in <module>
    assert out == func(inp)
AssertionError