I am only going to post the portion where the problem is at, the program has no error (all the codes are valid except for this raw_input problem)
I tested with search_function(1) and etc and it worked.
But if I do this while loop, it doesn't print anything. Example output:
Enter a number to print specific table, or STOP to quit: 2 Enter a number to print specific table, or STOP to quit: 2 Enter a number to print specific table, or STOP to quit: 1 Enter a number to print specific table, or STOP to quit: Enter a number to print specific table, or STOP to quit: 1 Enter a number to print specific table, or STOP to quit: Enter a number to print specific table, or STOP to quit: STOP
def search_function(x):
    if x == 1:
        for student in students:
            print "%-17s|%-10s|%-6s|%3s" % student.print_information()
        print '\n'
    if x == 2:
        print "%-17s|%-10s|%s" %(header[0],header[1],header[4])
        print "-" * 45
        for student in students:
            print "%-17s|%-10s|%s" %student.print_first()
        print '\n'
        print "Simple Analysis on favorite sports: "
        # Printing all sports that are specified by students
        for s in set(Student.sports): # class attribute
            print s, Student.sports.count(s), round(((float(Student.sports.count(s)) / num_students) *100),1)
        # Printing sports that are not picked 
        allsports = ['Basketball','Football','Other','Baseball','Handball','Soccer','Volleyball','I do not like sport']
        for s in set(allsports) - set(Student.sports):
            print s, 0, '0%'
        choice_list = Student.sports
        for choice in choice_list:
            choice_dict[choice] = choice_dict.get(choice, 0) + 1
        print max(choice_dict)
        print min(choice_dict)
    elif x == 3:
        print "%-17|%-10s|%-16s|%s" %(header[0],header[1],header[5],header[6])
        print "-" * 45
        for student in students:
            print "%-17s|%-10s|%-16s|%s" % student.print_second()
        print '\n'
    elif x == 4:
        print "%-17s|%-10s|%s" %(header[0],header[1],header[7])
        print "-" * 45
        for student in students:
            print "%-17s|%-10s|%s" %student.print_third()
        print '\n'
    elif x == 5:
        print "%-17s|%-10s|%-15s|%s" %(header[0],header[1],header[8],header[9])
        print "-" * 45
        for student in students:
            print "%-17s|%-10s|%-16s|%s" % student.print_fourth()
        print '\n'
x = raw_input("Enter a number to print specific table, or STOP to quit: ")
while x != 'STOP':
    search_function(x)
    x = raw_input("Enter a number to print specific table, or STOP to quit: ")