How to have multiple conditions for one if statement in python

Question

So I am writing some code in python 3.1.5 that requires there be more than one condition for something to happen. Example:

def example(arg1, arg2, arg3):
    if arg1 == 1:
        if arg2 == 2:
            if arg3 == 3:
                print("Example Text")

The problem is that when I do this it doesn't print anything if arg2 and arg3 are equal to anything but 0. Help?

Solution 1

I would use

def example(arg1, arg2, arg3):
     if arg1 == 1 and arg2 == 2 and arg3 == 3:
          print("Example Text")

The and operator is identical to the logic gate with the same name; it will return 1 if and only if all of the inputs are 1. You can also use or operator if you want that logic gate.

EDIT: Actually, the code provided in your post works fine with me. I don't see any problems with that. I think that this might be a problem with your Python, not the actual language.

Solution 2

Darian Moody has a nice solution to this challenge in his blog post:

a = 1
b = 2
c = True

rules = [a == 1,
         b == 2,
         c == True]

if all(rules):
    print("Success!")

The all() method returns True when all elements in the given iterable are true. If not, it returns False.

You can read a little more about it in the python docs here and more information and examples here.

(I also answered the similar question with this info here - How to have multiple conditions for one if statement in python)

Solution 3

Assuming you're passing in strings rather than integers, try casting the arguments to integers:

def example(arg1, arg2, arg3):
     if int(arg1) == 1 and int(arg2) == 2 and int(arg3) == 3:
          print("Example Text")

(Edited to emphasize I'm not asking for clarification; I was trying to be diplomatic in my answer. 🙂)

Solution 4

Might be a bit odd or bad practice but this is one way of going about it.

(arg1, arg2, arg3) = (1, 2, 3)

if (arg1 == 1)*(arg2 == 2)*(arg3 == 3):
    print('Example.')

Anything multiplied by 0 == 0. If any of these conditions fail then it evaluates to false.

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