How to perform encoding conversion in php? Brief analysis of methods

With the continuous development of the Internet, more and more websites are beginning to involve the processing of Chinese content. Among them, the processing of encoding format is an extremely important part. As a popular development language, PHP will inevitably involve Chinese coding issues. This article will introduce the basic concepts of PHP Chinese encoding format and how to convert it.

1. What is the encoding format?

The encoding format is the way the computer internally stores and processes characters. In computers, any characters are stored and transmitted in binary form. Different encoding formats use different binary sequences to represent characters. Therefore, when we need to process characters in the computer, we need to first convert the text form of the characters into the binary form inside the computer. This process is called encoding.

Commonly used encoding formats include ASCII, UTF-8, GBK, etc. Among them, ASCII is the earliest encoding format, which can only represent English letters and some common symbols, but cannot represent Chinese characters. UTF-8 and GBK are currently the most widely used Chinese encoding formats. UTF-8 is a variable-length encoding format that can represent all characters in the world and is one of the commonly used encoding formats on the Internet. GBK is a fixed-length encoding format that can only represent Chinese characters and some symbols. The difference between the two is the way characters are encoded.

2. How to perform encoding conversion

1. Character set conversion function

In PHP, you can use the iconv() function to perform encoding conversion. The syntax of this function is as follows:

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

This function converts $str from $in_charset encoding to $out_charset encoding, and The result is returned. For example, to convert a GBK-encoded string to a UTF-8-encoded string, you can use the following code:

$str = "中文字符";
$str = iconv("GBK", "UTF-8", $str);
echo $str;

2.mb_convert_encoding() function

is similar to the iconv() function , the mb_convert_encoding() function can also be used to perform encoding conversion. The syntax of this function is as follows:

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

The difference from the iconv() function is that mb_convert_encoding( ) function does not need to specify the encoding format of the source string when converting strings. Because this function will automatically detect the encoding format of the source string and convert it. For example, to convert a GBK-encoded string to a UTF-8-encoded string, you can use the following code:

$str = "中文字符";
$str = mb_convert_encoding($str, "UTF-8", "GBK");
echo $str;

3. Notes on Chinese encoding format

1. Source encoding To correctly

the conversion of encoding format must be based on the premise that the source encoding is correct. If the source encoding is incorrect, then any transcoding will have no effect. For example, if a string encoded in UTF-8 is actually stored in GBK encoding, then when converting, you need to first decode the string into a character set using GBK encoding, and then perform encoding conversion.

2. The target encoding must be appropriate

When performing encoding conversion, an appropriate target encoding must be selected. Typically, UTF-8 is the most suitable encoding format. Because UTF-8 can not only represent Chinese characters, but also all characters in the world. In addition, UTF-8 is the most widely used on the Internet and can ensure data compatibility.

3. Avoid multiple conversions

In practical applications, we need to avoid multiple encoding conversions as much as possible. Because each conversion consumes a lot of CPU resources and is prone to conversion errors. When performing encoding conversion, you should try to process data with the same source encoding and target encoding to avoid multiple conversions.

In short, correctly processing the Chinese encoding format is one of the important prerequisites for Chinese processing. In PHP, you can use the iconv() function and mb_convert_encoding() function to perform encoding conversion. However, when performing encoding conversion, you need to pay attention to the correctness of the source encoding and the suitability of the target encoding to avoid multiple conversions.

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