# Vowel

- `v::vowel()`

Similar to `v::alnum()`. Validates strings that contains only vowels:

```php
v::vowel()->validate('aei'); // true
```

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See also:

  * [Alnum](Alnum.md)
  * [Alpha](Alpha.md)
  * [Consonant](Consonant.md)
  * [Digit](Digit.md)