Detailed introduction to the use of PHP replacement function

The PHP replacement function searches for a specified string in a string and replaces all matching strings with another string. Not only can you use these functions to replace strings, you can also manipulate values ​​in arrays. This article will introduce in detail how to use PHP replacement function.

1. PHP replace() function

PHP replace() function is a string replacement function, used to search for another string in a string and replace it with the specified String. The replace() function is very simple to use. You only need to pass three parameters to the function: the string to be found, the string to be replaced, and the string to be operated on. Here is a simple example:

$str = "Hello World!";
echo str_replace("World", "PHP", $str);
?>

In this example, we use the str_replace() function to replace "World" in the string with "PHP". The output is "Hello PHP!", just as we would expect.

2. PHP preg_replace() function

In addition to the str_replace() function, PHP also provides the preg_replace() function, which can use regular expressions to replace strings. Regular expressions are a very powerful tool that can be used to match various complex patterns. The preg_replace() function is similar to the str_replace() function. You only need to pass in the pattern to be matched and the replacement pattern as parameters. Here is a simple example:

$str = "The quick brown fox jumps over the lazy dog.";
echo preg_replace("/\s/", " -", $str);
?>

In this example, we use the preg_replace() function to replace all spaces in the string with "-". The output result is "The-quick-brown-fox-jumps-over-the-lazy-dog."

3. PHP strtr() function

strtr() function is another commonly used The replacement function, which replaces a single character in a string with another character. This function needs to be passed two parameters: the first is the string to be operated on, and the second is an array consisting of old characters and new characters. Here is a simple example:

$str = "Hello World!";
echo strtr($str, "elo", "123");
?>

In this example, we use the strtr() function to replace "e", "l" and "o" in the string with "1", "2" and "3". The output result is "H123 123rld!"

4. PHP str_replace_array() function

The str_replace_array() function is a variant of the str_replace() function, which can accept an array as a search character string and an array as the replacement string. The usage of this function is the same as the str_replace() function. You only need to pass in the string to be operated on, the search string array and the replacement string array. Here is a simple example:

$searchArray = ['World', 'PHP'];
$replaceArray = ['Universe', 'Web Development'];
$str = "Hello World! Learn PHP.";
echo str_replace_array($searchArray, $replaceArray, $str);
?>

In this example, we use The str_replace_array() function replaces "World" in the string with "Universe" and "PHP" with "Web Development". "Hello World! Learn PHP." will be replaced with "Hello Universe! Learn Web Development."

In short, PHP provides a variety of replacement functions, which can be selected and used according to actual needs. Whether you are replacing characters in a string or using regular expressions, PHP provides convenient and simple methods.

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