Consider tuple iteration #930
Comments
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It doesn't really need to be syntax sugar. If it's done as an IntoIterator impl on tuples then it's not exactly syntax, is it? I've written code like: too many times. This would be much appreciated and make iterating over several iterables at once far easier to read, in my opinion. |
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I would love to see this. Zip syntax right now is kind of ugly and unreadable, IMHO. I almost prefer to use indices instead of iterators half the time. I don't think there's any reason why we couldn't have both. |
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See #1650 which presents one way to do this. |
nrc
added
T-lang
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I'm not really sure I see how that would make this possible. I'm just looking for an impl of That is, for x in (&[1, 2, 3], &[4, 5, 6]) {
println!("{:?}", x);
}would be equivalent to for x in (&[1,2,3]).into_iter().zip(&[4,5,6]) {
println!("{:?}", x);
} |
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Ah sorry, I misunderstood what you were asking for. What I had in mind was somelike like a |
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Should rust-lang/rust#43242 be part of this RFC or a separate one? |
This makes it a little easier to `zip` iterators:
```rust
for (x, y) in (xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```
You can iterate `(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:
```rust
for ((x, y), z) in ((xs, ys), zs) {}
for (x, (y, z)) in (xs, (ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```
Only tuple pairs are implemented for now. It's possible to implement
longer tuples, but that would require a new iterator type to produce
those tuple items. See itertools' [`Zip`] and rayon's [`MultiZip`] for
prior art there.
[`Zip`]: https://docs.rs/itertools/0.9.0/itertools/structs/struct.Zip.html
[`MultiZip`]: https://docs.rs/rayon/1.4.1/rayon/iter/struct.MultiZip.html
See also rust-lang/rfcs#870 and rust-lang/rfcs#930.
Original proposed in #870, some syntax sugar for iterating over multiple things.
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