reverse integers with tail recurse

reverse_integers.py

#  Execice for tail recurse
# Reverse the integr, strip 0 
# if 0 is the first num
# 
# e.g: 123450 --> 54321


def reverse(n):
    s=list(str(n))
    length = len(s)
    r_index = length-1
    for index, v in enumerate(s):
        if index >= r_index:
            break
        s[index], s[r_index] = s[r_index], s[index]
        r_index -= 1
    return int(''.join(s))

def reverse_recurse(n, res=None):
    if n/10==0:
        return res
    if res:
        res = res*10 + n%10
    else:
        res = n%10
    return reverse_tail_recurse(n/10, res)


def reverse_tail_recurse(n, res=None):
    #print(n, res)

    if res:
        res = res*10 + n%10
    else:
        res = n%10
    if n/10==0:
        return res
    return reverse_tail_recurse(n/10, res)