in - Rust
Description: Iterate over a series of values with `for`.
Keywords: rust, rustlang, rust-lang, in

# Keyword in

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Iterate over a series of values with `for`.

The expression immediately following `in` must implement the `IntoIterator` trait.

### Literal Examples:

- `for _ in 1..3 {}` - Iterate over an exclusive range up to but excluding 3.
- `for _ in 1..=3 {}` - Iterate over an inclusive range up to and including 3.

(Read more about range patterns)

The other use of `in` is with the keyword `pub`. It allows users to declare an item as visible only within a given scope.

### Literal Example:

- `pub(in crate::outer_mod) fn outer_mod_visible_fn() {}` - fn is visible in `outer_mod`

Starting with the 2018 edition, paths for `pub(in path)` must start with `crate`, `self` or `super`. The 2015 edition may also use paths starting with `::` or modules from the crate root.

For more information, see the Reference.