[Tutor] if-else statements

[andrade1@umbc.edu]

Hello

I'm having some trouble with my if, else statements. For some reason, the
months that have 31 days work fine, but the months that have 28/30 do not
work. Am I doing something wrong? it is supposed to take a date as an
input like 9/31/1991 and then say that the date is not valid because
september only has 30 days.

import string

def main():
    # get the day month and year
    month, day, year = input("Please enter the mm, dd, yyyy: ")
    date1 = "%d/%d/%d" % (month,day,year)

    months = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

    if day <= months[1]:
        d = "valid"
    else:
        n = "not valid"

    if day <= months[2]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[3]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[4]:
        d = "valid"
    else:
        n = "not valid"

    if day <= months[5]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[6]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[7]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[8]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[9]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[10]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[11]:
        d = "valid"
    else:
        d = "not valid"

    if day <= months[12]:
        d = "valid"
    else:
        d = "not valid"

    print "The date you entered", date1, "is", d +"."

main()