If condition code, how common is it to write like this?

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#1

Hello

This code below:

if 10000 < user_ratings <= 100000:

How common is it for Python developers to write that piece of code instead of writing:

if user_rating > 10000 and user_rating <= 100000

Regards,
Lee

#2

Can’t really say how common this would be, but I would assume fairly common. This is actually mentioned in the official documentation, so knowing this would be better -

Comparisons can be chained arbitrarily, e.g., x < y <= z is equivalent to x < y and y <= z , except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false).

And because of that statement above (and Python’s underlying code/optimization) -

except that y is evaluated only once

The x < y <= z approach is faster than using the and approach.

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#4

Thanks for your reply.

What really got to me was this way of coding:

if 100000 < user_ratings <= 500000:
        user_ratings_freq['100000 - 500000'] +=1

I’ve been used to something like this, in Pascal, VISUAL BASIC, :

if user_ratings >= 100000 and user_rating <= 500000:
        user_ratings_freq['100000 - 500000'] +=1

I guess I need to look at the former code and think, if 99999 or less, is less than what is in user_rating. So say that it is true. Then if user_rating is also less than or equal to 500000, then add 1 to current count.

Am I right?

Regards
Lee

#5

Not quite accurate. 100000 is a fixed value. So you can’t say if 99999 or less is less than what is in user_rating. Because, if you phrase it that way, it implies that you are considering the 99999 to be variable.

Better to state that user_rating is more than 100000 and less than or equal to 500000.

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