How to convert string to lowercase in php (two situations)

PHP is a programming language famous for developing web applications. It not only has powerful functions, but is also easy to learn and use. When performing string operations, sometimes it is necessary to convert the string into lowercase letter form. In this article, we will discuss how to convert a string to lowercase using PHP.

1. Use the strtolower() function to convert a string to lowercase form

In PHP, you can use the strtolower() function to convert a string to lowercase form. The syntax of this function is as follows:

string strtolower (string $string)

This function has only one parameter $string, which indicates the string to be converted to lowercase. Here is a simple example:

$str = "CONVERT ME TO lowercase";
$str = strtolower($str);
echo $str;

In this example, we convert all strings to lowercase and print the result "convert me to lowercase" on the screen.

2. Use the mb_strtolower() function to convert multi-byte strings

When dealing with multi-byte strings, there is a better choice when converting strings to lowercase Use the mb_strtolower() function. This function can handle strings in different languages ​​and convert them to lowercase. The syntax of this function is as follows:

string mb_strtolower ( string $str [, string $encoding = mb_internal_encoding() ] )

This function has two parameters: $str and $encoding. The $str parameter indicates the string to be converted to lowercase, and the $encoding parameter indicates the character encoding to be used. If the $encoding parameter is not provided, PHP's internal character encoding is used by default. The following is a simple example:

$str = "转换我成小写字母形式";
$str = mb_strtolower($str, "UTF-8");
echo $str;

In this example, we use the mb_strtolower() function and convert the string to lowercase letters. When printing the output, we can get the lowercase version of "convert me to lowercase".

Summary

Whether you are dealing with single-byte or multi-byte strings, PHP provides simple and easy-to-use functions to convert strings to lowercase. When dealing with multi-byte strings, using the mb_strtolower() function is a better choice. Hope this article is helpful to you.

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