<python> or operator- another stupid question

[adarw]

Another stupid question but this time its on the or operator.

 

import sys
num = (int(input("Enter the car number model or enter 0 to quit: ")))
if num == (221) or (780):
  print ("defective")
elif num == (123): 
  print ("working")
elif num == (0): 
  sys.exit()
else:
  print ("invaild number")
  

 

so when running this code for some reason it always replies with defective, i had done some trobleshooting and it turns out that just deleting the

 

or (780)

 

makes it work perfectly, now i can do another elif and just call it a day but what is wrong?

 

 

also can i make a thread with stupid questions about my problems cause making a new thread each time is kinda tiring...

[Logical92]

Hi! 

The problem is the the way you are reading it vs program reads it.

if num == (221) or (780):

You read this as if the number is equal to either of these two numbers

But, python reads this as

if number equals 221

or

if 780

When a number is by itself if it's not zero it's considered true, kind of a throwback to lower level languages even though it doesn't make a lot of sense on its face.

[adarw]

3 minutes ago, Logical92 said:

Hi! 

The problem is the the way you are reading it vs program reads it.

if num == (221) or (780):

You read this as if the number is equal to either of these two numbers

But, python reads this as

if number equals 221

or

if 780

When a number is by itself if it's not zero it's considered true, kind of a throwback to lower level languages even though it doesn't make a lot of sense on its face.

ohhhhh that makes sense, thank you so much. this is how its supposed to be right? 

if num == (221) or num == (780):

 

8 minutes ago, Logical92 said:

When a number is by itself if it's not zero it's considered true

oh i didnt know that. thanks

[Kilrah]

21 minutes ago, adarw said:

ohhhhh that makes sense, thank you so much. this is how its supposed to be right? 

Correct, note the parentheses aren't needed.

[delph]

Yeah, you can lighten up on the outside parentheses - they're needed for functions - like print() - and you'll use them in math as you're used to - (1+2)*3

These lines:

num = (int(input("Enter the car number model or enter 0 to quit: ")))
if num == (221) or num == (780):

Will work just fine as:

num = int(input("Enter the car number model or enter 0 to quit: "))
if num == 221 or num == 780:

[Logical92]

Also, now that I am a real keyboard.

To be clear, what I said only applies to inside an if statement.

if statement:

Whatever is "statement" tries to be converted into a true or false.

When it comes to integers 0 == false and anything else == true.

http://anh.cs.luc.edu/python/hands-on/3.1/handsonHtml/boolean.html

This link shows a lot of examples as to how things get converted, they even have one that is almost Identical to your issue!

I would recommend giving it a read if you want to better understand python booleans!