# icu_plurals [](https://crates.io/crates/icu_plurals)
[`icu_plurals`](crate) is one of the [`ICU4X`] components.
This API provides functionality to determine the plural category
appropriate for a given number in a given language.
For example in English language, when constructing a message
such as `{ num } items`, the user has to prepare
two variants of the message:
* `1 item`
* `0 items`, `2 items`, `5 items`, `0.5 items` etc.
The former variant is used when the placeholder variable has value `1`,
while the latter is used for all other values of the variable.
Unicode defines [`Language Plural Rules`] as a mechanism to codify those
variants and provides data and algorithms to calculate
appropriate [`Plural Category`].
## Examples
```rust
use icu::locid::macros::langid;
use icu::plurals::{PluralRules, PluralRuleType, PluralCategory};
let lid = langid!("en");
let provider = icu_testdata::get_provider();
let pr = PluralRules::try_new(lid, &provider, PluralRuleType::Cardinal)
.expect("Failed to construct a PluralRules struct.");
assert_eq!(pr.select(5_usize), PluralCategory::Other);
```
### Plural Rules
The crate provides the main struct [`PluralRules`] which handles selection
of the correct [`Plural Category`] for a given language and [`Plural Type`].
### Plural Category
Every number in every language belongs to a certain [`Plural Category`].
For example, Polish language uses four:
* [`One`](PluralCategory::One): `1 miesiąc`
* [`Few`](PluralCategory::Few): `2 miesiące`
* [`Many`](PluralCategory::Many): `5 miesięcy`
* [`Other`](PluralCategory::Other): `1.5 miesiąca`
### Plural Rule Type
Plural rules depend on the use case. This crate supports two types of plural rules:
* [`Cardinal`](PluralRuleType::Cardinal): `3 doors`, `1 month`, `10 dollars`
* [`Ordinal`](PluralRuleType::Ordinal): `1st place`, `10th day`, `11th floor`
[`ICU4X`]: ../icu/index.html
[`Plural Type`]: PluralRuleType
[`Plural Category`]: PluralCategory
[`Language Plural Rules`]: https://unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules
[`CLDR`]: http://cldr.unicode.org/
## More Information
For more information on development, authorship, contributing etc. please visit [`ICU4X home page`](https://github.com/unicode-org/icu4x).