What are the best practices for constructing regular expressions in PHP?

When constructing regular expressions in PHP, it is important to follow best practices to ensure they are efficient and effective. Some key tips include using anchors (^ and $) to match the beginning and end of a string, using character classes ([ ]) to specify a set of characters to match, escaping special characters (\) when needed, and using quantifiers (+, *, ?) to specify repetition. 

// Example of constructing a regular expression in PHP
$pattern = '/^hello [Ww]orld$/'; // Match strings that start with "hello" followed by a space and then "World" or "world"
$string = "Hello World";

if (preg_match($pattern, $string)) {
    echo "Match found!";
} else {
    echo "No match found.";
}

Keywords

regular expressions PHP construction patterns validation

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