A brief analysis of how to convert PHP string encoding

In the process of web development, we often encounter situations where string encoding needs to be converted, such as converting an ISO-8859-1 encoded string to a UTF-8 encoded string. In PHP, some functions are provided to handle string encoding conversion issues. This article will explain how to convert a string encoding to another encoding using PHP.

1. mb_convert_encoding function

The mb_convert_encoding function is one of the functions in PHP used to convert string encodings. This function converts a string from one encoding to another. The syntax of the function is as follows:

string mb_convert_encoding ( string $str , string $to_encoding [, mixed $from_encoding = mb_internal_encoding() ] )

Among them, the $str parameter is the string that needs to be encoded and converted, the $to_encoding parameter is the target encoding after conversion, and the $from_encoding parameter indicates the encoding format currently used by $str. If If not specified, the encoding format specified in mb_internal_encoding() will be used by default.

The following is a sample code to convert an ISO-8859-1 encoded string to a UTF-8 encoded string:

$str = "Hello, 你好！";
$str_utf8 = mb_convert_encoding($str, "UTF-8", "ISO-8859-1");
echo $str_utf8;

The output result is:

Hello, 你好！

2. iconv function

iconv function is also one of the functions used for string encoding conversion in PHP. This function converts a string from one encoding to another. The syntax of the function is as follows:

string iconv ( string $in_charset , string $out_charset , string $str )

Among them, the $in_charset parameter indicates the encoding format currently used by $str, the $out_charset parameter indicates the target encoding after conversion, and the $str parameter is the string that needs to be encoded.

The following is a sample code to convert an ISO-8859-1 encoded string to a UTF-8 encoded string:

$str = "Hello, 你好！";
$str_utf8 = iconv("ISO-8859-1", "UTF-8", $str);
echo $str_utf8;

The output result is:

Hello, 你好！

3. Use the mb_string library

PHP also provides the mb_string library, which provides a series of functions for processing multi-byte character sets, including strings Transcoding. For example, the mb_convert_variables function can convert one or more variables from one string encoding to another. The syntax of the function is as follows:

mixed mb_convert_variables ( string $to_encoding , mixed $from_encoding , mixed &$vars [, mixed &...$vars ] )

Among them, the $to_encoding parameter is the target encoding after conversion, the $from_encoding parameter indicates the current encoding format of the string in the $vars array, and the $vars parameter is the string that needs to be encoded. Variable, supports multiple variables.

The following is a sample code that converts two ISO-8859-1 encoded strings into UTF-8 encoded strings:

$str1 = "Hello, ";
$str2 = "你好！";
mb_convert_variables("UTF-8", "ISO-8859-1", $str1, $str2);
echo $str1 . $str2;

The output result is:

Hello, 你好！

Summary

PHP provides a variety of functions for processing string encoding conversion. Developers can choose the appropriate method to implement based on actual needs. It should be noted that when performing string encoding conversion, you need to ensure that the current encoding format of the string to be converted and the converted target encoding format are correct.

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