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# Length

- `Length(Validator $validator)`

Validates the length of the given input against a given validator.

```php
v::length(v::between(1, 5))->assert('abc');
// Validation passes successfully

v::length(v::greaterThan(5))->assert('abcdef');
// Validation passes successfully

v::length(v::lessThan(5))->assert('abc');
// Validation passes successfully
```

This validator can be used to validate the length of strings, arrays, and objects that implement the `Countable` interface.

```php
v::length(v::greaterThanOrEqual(3))->assert([1, 2, 3]);
// Validation passes successfully

v::length(v::equals(0))->assert(new SplPriorityQueue());
// Validation passes successfully
```

## Templates

### `Length::TEMPLATE_STANDARD`

Used when it's possible to get the length of the input.

|       Mode | Template      |
| ---------: | :------------ |
|  `default` | The length of |
| `inverted` | The length of |

### `Length::TEMPLATE_WRONG_TYPE`

|       Mode | Template                                      |
| ---------: | :-------------------------------------------- |
|  `default` | {{subject}} must be countable or a string     |
| `inverted` | {{subject}} must not be countable or a string |

## Template as prefix

The template serves as a prefix to the template of the inner validator.

```php
v::length(v::equals(3))->assert('tulip');
// → The length of "tulip" must be equal to 3

v::not(v::length(v::equals(4)))->assert('rose');
// → The length of "rose" must not be equal to 4
```

### `Length::TEMPLATE_WRONG_TYPE`

Used when it's impossible to get the length of the input.

| Mode       | Template                                              |
| ---------- | ----------------------------------------------------- |
| `default`  | {{subject}} must be a countable value or a string     |
| `inverted` | {{subject}} must not be a countable value or a string |

## Template placeholders

| Placeholder | Description                                                      |
| ----------- | ---------------------------------------------------------------- |
| `subject`   | The validated input or the custom validator name (if specified). |

## Categorization

- Comparisons
- Transformations

## Changelog

| Version | Description             |
| ------: | :---------------------- |
|   3.0.0 | Became a transformation |
|   0.3.9 | Created                 |

## See Also

- [All](All.md)
- [Between](Between.md)
- [BetweenExclusive](BetweenExclusive.md)
- [Each](Each.md)
- [GreaterThan](GreaterThan.md)
- [GreaterThanOrEqual](GreaterThanOrEqual.md)
- [LessThan](LessThan.md)
- [LessThanOrEqual](LessThanOrEqual.md)
- [Max](Max.md)
- [Min](Min.md)