Splitting variants of str::starts_with and ends_with

[gkoz]

More often than not, when using starts_with or ends_with I actually want to do something with the remaining slice and have to split it out manually, e.g.:

    if s.starts_with(prefix) {
        let part = &s[prefix.len()..];
        // ...
    }

it would be more convenient to just do

    if let Some(part) = s.starts_split(prefix) {
        // ...
    }

[Diggsey]

That does seem like a much rustier approach.

[tafia]

I like this too.
No sure about the name (split usually returns an array)

[diaphore]

No sure about the name (split usually returns an array)

There's already a bunch of split (some of them unstables) : split_first*, split_at* ... split_prefix would fit nicely.

[withoutboats]

Tracking issues for related features:

• str::split_at
• slice_splits (including slice::split_first, which is similar to this)