What is the difference between using str_replace and preg_replace in PHP for replacing text?

When replacing text in PHP, the main difference between str_replace and preg_replace is the way they handle the search pattern. str_replace performs a simple text search and replace, while preg_replace allows for more complex pattern matching using regular expressions. If you need to replace simple text strings, str_replace is sufficient. However, if you need to perform more advanced text replacements based on patterns, preg_replace is the better choice.

// Using str_replace to replace a simple text string
$text = "Hello, World!";
$new_text = str_replace("Hello", "Hi", $text);
echo $new_text;

// Using preg_replace to replace based on a regular expression pattern
$text = "The quick brown fox jumps over the lazy dog.";
$new_text = preg_replace("/brown fox/i", "red fox", $text);
echo $new_text;