What is the significance of the s modifier in a regular expression pattern when matching characters in PHP?

The s modifier in a regular expression pattern in PHP is significant when matching characters, as it allows the dot metacharacter (.) to match newline characters (\n). By default, the dot metacharacter does not match newline characters, so using the s modifier is necessary when you want the dot to match newlines as well. This can be useful when working with multi-line strings or when you want to match a pattern that spans multiple lines. 

// Using the s modifier to match newline characters with the dot metacharacter
$pattern = '/pattern/s';
$string = "This is a multi-line\nstring";
if (preg_match($pattern, $string)) {
    echo "Pattern found in the string.";
} else {
    echo "Pattern not found in the string.";
}

Keywords

PHP regular expression s modifier matching characters significance

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