Python'da regexlardan foydalanmasdan satrda eng katta butun sonni qanday topish mumkin?

Regulyar ifodalar ishlatmasdan satrda eng katta butun sonni topish uchun, satrning harflari bo'ylab yurib, raqamlar ketma-ketligini ajratib, ularni sonlarga aylantirib, maksimalini kuzatib borish mumkin.

Python misoli:

def max_integer_in_string(s):
    max_num = None
    current_num = ''
    for ch in s:
        if ch.isdigit():
            current_num += ch
        else:
            if current_num:
                num = int(current_num)
                if max_num is None or num > max_num:
                    max_num = num
                current_num = ''
    # Tsikldan keyin tekshirish, agar satr raqam bilan tugasa
    if current_num:
        num = int(current_num)
        if max_num is None or num > max_num:
            max_num = num
    return max_num

# Foydalanish misoli
s = "abc123def45gh6789"
print(max_integer_in_string(s))  # 6789 ni chiqaradi