If logic in python

Question

I have a quick question regarding if logic in python. I have the following code:


    def punch(self):
        """Punch method that returns different remarks based on glove weight"""

        if self.weight < 5:
            return "That tickles."
        elif self.weight >= 5 & self.weight < 15:
            return "Hey that hurt!"
        else:
            return "OUCH!"

When I run the following code it always returns “Hey that hurt!”, no matter what weight I assign to self.weight. I am extremely confused as to why that is.

Instead of using `&`, what happens if you use `and`? Also, instead of using `|`, what happens if you use `or`? [Here](https://docs.python.org/3/reference/expressions.html#boolean-operations) is a little more information from the documentation, if it helps! I think `&` [means something different](https://docs.python.org/3/reference/expressions.html#binary-bitwise-operations) than what you might have been expecting, for Python. — summea, Feb 13 '21 at 01:51
Your question talks about assert statements (which are in fact an actual thing in Python), whereas you have shown if statements. Please stick to standard terminology, this is confusing. — costaparas, Feb 13 '21 at 01:53
Where exactly did you get the idea to use `&`, was it in some tutorial? You almost certainly intended to use the boolean `and` operator instead. (`&` is the bitwise AND). — costaparas, Feb 13 '21 at 02:00
I honestly didn't know the difference between the two which has now been clarified. My question is why does adding partheses change the behavior? — , Feb 13 '21 at 02:11

score 1 · Accepted Answer · answered Feb 13 '21 at 01:54

&, |, etc. are bitwise operators, used for things like bit-flipping, etc.

and, or, not, etc. are logical operators, and are what you likely mean to use in situations like these.

Also, as a side note, assert, as you've called it in the title, is something else entirely from logic statements like the ones you've presented.

score 1 · Answer 2 · answered Feb 13 '21 at 01:55

1

There is difference between the two operators in Python: & (bitwise AND) and and (boolean AND). & has a higher precedence than and which is why your code behaves differently. Learn more about operator precedence here.

answered Feb 13 '21 at 01:55

AnkurSaxena

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score 0 · Answer 3 · answered Feb 13 '21 at 01:55

In Python, I think you would want to use the terms and or or instead of & and | for what it looks you are wanting to do.

In this particular language, & and | appear to be bitwise operations instead of boolean operations, like I was getting at in my earlier comments.

If logic in python

3 Answers3