迭代并修改切片

Once you hold a slice, you usually want to visit every element. Zig's for loop iterates a slice cleanly from start to end. 🔁

Put the slice in parentheses and name each element with a capture in pipes. The loop hands you one value per pass.

A plain capture gives you a copy of each element. Changing that copy does not touch the slice's underlying data.

Add * before the capture name to get a pointer instead of a copy. Now writing through it edits the real element.

With a pointer capture you use .* to reach the value it points at. That syntax lets you both read and assign.

To change elements the slice type must be plain []T, not []const T. A const slice forbids writing through it.

Pair the slice with a range to also get a counter. The second capture after the comma is the current index.

You can also write to a slot by index without a loop capture. Assign through the brackets just like an array.

Pass several slices to one for loop to walk them in lockstep. They must share the same length or it panics.

Keep a running total in a var declared before the loop, then update it on each pass to compute a sum.

Inside the loop, continue jumps straight to the next element. Use it to ignore values that fail a quick test.

You want to double every element of a []i32 slice in place. Which capture form lets you write back?

Loop a slice with for: plain captures read copies, |*value| with .* mutates in place, and add a range to track the index. 🎯