Python if and else print condition

Question

If an integer is divisible by 3, print "Hi"

If it is divisible by 7, print "Bye"

If it is divisible by both 3 and 7, print "HiBye"

As of now I have tried:

for i in range(1,100):
    if i % 3 == 0:
        print "Hi"
    if i % 7 == 0:
        print "Bye"
    if i % 3 == 0 and i % 7 == 0:
        print "HiBye"
    else: 
        print i

But my numbers are repeated. i.e. this is the output I get.

1
2
Hi
3
4
5
Hi
6
Bye
7
8
Hi
9
10
11
Hi
12
13
Bye
14
Hi
15
16
17
Hi
18
19
20
Hi
Bye
HiBye

As you can see, the 3 is repeated again. I think the mistake is in the

else:
    print i

statement

Answer 1

You need to use elif instead of if, and test for the 3 and 7 case first:

if i % 3 == 0 and i % 7 == 0:
    print "HiBye"
elif i % 3 == 0:
    print "Hi"
elif i % 7 == 0:
    print "Bye"
else: 
    print i

You used independent if statements. Each if statement is tested and their block is executed, regardless of what other if statements your code may execute before or after. elif blocks, however, are attached to their if statement and Python will only ever execute one of the blocks, the first one whose condition is true.

So in the above if..elif..elif..else series of tests, if i % 3 == 0 and i % 7 == 0 is True, none of the other branches will be executed, including the else branch.

Now the output looks like:

>>> for i in range(1, 22):
...     if i % 3 == 0 and i % 7 == 0:
...         print "HiBye"
...     elif i % 3 == 0:
...         print "Hi"
...     elif i % 7 == 0:
...         print "Bye"
...     else:
...         print i
...
1
2
Hi
4
5
Hi
Bye
8
Hi
10
11
Hi
13
Bye
Hi
16
17
Hi
19
20
HiBye

Answer 2

If I understand you right, these are the conditions: 1) if the number is divisible by 3 print "Hi" 2) if the number is divisible by 7 print "Bye" 4) if the number is divisible by 3 and 7 print "HiBye" 5) if none of the above conditions are met, print the number.

for i in range(1,100):
if i % 3 == 0 and i % 7 == 0:
    print "HiBye"
elif i % 3 == 0:
    print "Hi"
elif i % 7 == 0:
    print "Bye"

elif i % 3 != 0 and i % 7!= 0:
    print i

This code works for the above conditions. It states them explicitly and forces the logic.

Answer 3

You need to change you code to

for i in range(1,100):
    if i % 3 == 0 and i % 7 == 0:
        print "HiBye"
    elif i % 3 == 0:
        print "Hi"
    elif i % 7 == 0:
        print "Bye"
    else: 
        print i

Because otherwise it will individually look at each if statement and when its on 3 for example it does the first part of code but when it triesif i % 3 == 0 and i % 7 == 0:it will be false so it prints i