What best practices should be followed when using regular expressions with \s in PHP?

When using regular expressions with \s in PHP, it is important to remember that \s matches any whitespace character, including spaces, tabs, and line breaks. To ensure that the regular expression behaves as expected, it is recommended to use the \s metacharacter within a character class [] to explicitly define the whitespace characters you want to match. This helps to avoid unexpected matches and ensures more precise pattern matching. 

// Example of using \s within a character class to match only spaces and tabs
$string = "Hello world";
if (preg_match('/[ \t]/', $string)) {
    echo "Match found!";
} else {
    echo "No match found.";
}

Keywords

regular expressions \s PHP whitespace characters validation

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