cmp::Ordering vs comparison symbols
from alertsleeper@programming.dev to rust@programming.dev on 07 Jan 2024 21:31
https://programming.dev/post/8269174
from alertsleeper@programming.dev to rust@programming.dev on 07 Jan 2024 21:31
https://programming.dev/post/8269174
beginner question: What is the advantage of using cmp::Ordering::Less over “<”, same for Greater and Equals?
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Here’s a good example.
Basically,
cmp::Ordering::Less
is an enum so a match using it is guaranteed to be exhaustive, whereas you need to be careful when doing an if/else chain that you cover all cases.What language?(I’m an idiot) If you’re referring to Rust,std::cmp::Ordering
is an enum and can be used withPartialOrd
/Ord
to see how two values compare. The comparison operators basically call yourpartial_ord
implementation. If you can use the operators themselves, use them instead of callingpartial_ord
in most cases.In other languages, I don’t know, but I assume in general if you can use the operators, you should (unless you’re interested specifically in their ordering, not whether one is only one of greater than, equal to, or less than another).I’m guessing you’re asking because you got a clippy lint. Using
Ordering
allows you tomatch
the output therefore only callingpartial_ord
once, compared to using an if-else chain which might call it several times. In many/most cases this would probably be compiler optimized anyway but this makes it explicit.