What are the differences between using shorthand character classes like \d and explicit character ranges like [0-9] in PHP regular expressions?

Using shorthand character classes like \d is more concise and easier to read compared to explicit character ranges like [0-9]. Shorthand character classes are also more portable across different regex flavors. However, explicit character ranges provide more control and customization over the characters matched. It is recommended to use shorthand character classes for simplicity and readability, but explicit character ranges can be used when specific customization is needed.

// Using shorthand character class \d
$pattern = '/^\d{3}-\d{2}-\d{4}$/';

// Using explicit character range [0-9]
$pattern = '/^[0-9]{3}-[0-9]{2}-[0-9]{4}$/';