parse_digits.py

english_digits = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']

# check if string s1 starts with s2
def startswith(s1, s2):
    if len(s2) > len(s1):
        return False
    for i in range(len(s2)):
        if s1[i] != s2[i]:
            return False
    return True


def parse_integer(s):
    digits = []
    while len(s) > 0:
        for ind, digit in enumerate(english_digits):
            if startswith(s, digit):
                digits.append(str(ind))
                # truncate the string
                s = s[len(digit):]
    return int(''.join(digits))


def to_my_string(p):
    # think about why we need this
    if p == 0:
        return english_digits[0]

    s = []

    while p > 0:
        lowest_digit = p % 10
        p = p // 10 # division and floor operation (/ operation in Java/C++)
        # e.g. 5/2=2
        s.append(english_digits[lowest_digit])

    s.reverse()
    return ''.join(s)


print(parse_integer('onetwothreefourfiveseventwo'))
print(to_my_string(5130798273))