On: Learning Rust via Advent of Code

[terhechte]

This is awesome. How did you figure this out? The documentation on `split` says:

"The pattern can be a &str, char, or a closure that determines the split."

But in your case it is an array of chars and it splits for each of them. I don't see this documented at all.

[general_pizza → terhechte]

The docs are a tad misleading but the important piece is to look at the signature. The `where P: Pattern<'a>` portion states that split needs a type that implements the Pattern trait. If you follow the link to the Pattern trait then at the bottom you'll see a section[0] listing types implementing the trait (&[char] being one) and therefore can be passed into split. Hope that helps!

[0] https://doc.rust-lang.org/std/str/pattern/trait.Pattern.html...

[steveklabnik → terhechte]

Would you be willing to file a docs bug so we can clarify this?

It’s possible that it used to be only those types, but was expanded. We should fix this!

[terhechte → steveklabnik]

Yeah, will do

[steveklabnik → terhechte]

Awesome, thank you!

[gridspy → terhechte]

Vec<char> or an array for instance - [char; 20] can (automatically) create a "slice" of type &[char]. This is true for all types (not just char).

The operator for this is for eg l[1..10]. It can also happen automatically.

&str is the same type as &[char] - just a renaming.

Still learning Rust myself, apologies if this leads you astray. Just do some reading on slices.

https://doc.rust-lang.org/book/ch04-03-slices.html#string-sl...

https://doc.rust-lang.org/std/slice/

[steveklabnik → gridspy]

&str is not the same as &[char]. &str has the same memory representation as &[u8]. char is four bytes, not one.

[gridspy → steveklabnik]

Thanks Steve.

[steveklabnik → gridspy]

No problem! It's an easy mistake to make.