In the process of text processing, it is a common requirement to convert strings in different encoding formats. The iconv (Internationalization Conversion) function provided in the PHP language can meet this need very conveniently. This article will introduce the use of iconv function in detail from the following aspects:

1. Definition of iconv function and introduction to common parameters
2. Example demonstration: Convert GBK encoded string to UTF -8 encoded string
3. Example demonstration: Convert UTF-8 encoded string to GBK encoded string
4. Under what circumstances do you need to use the iconv function

1. Definition of iconv function and introduction to common parameters

1. Definition of iconv

iconv function can convert between different character set encodings. Its definition is as follows ：

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

Among them:

• $in_charset: Represents the character encoding format of the original string.
• $out_charset: Indicates the character encoding format of the target string.
• $str: Indicates the string that needs to be converted.

2. Common parameters of iconv function

(1)$in_charset and $out_charset

Characters that can usually be used in $in_charset and $out_charset The set encodings are:

• UTF-8: A variable-length encoding method of Unicode encoding, usually used to transmit Unicode characters in web pages, emails, XML and other applications.
• GB2312: Simplified Chinese character set, including 6,763 Chinese characters.
• BIG5: Traditional Chinese character set, including 13,053 Chinese characters and some other characters.
• ISO-8859-1: Western European character set, including 256 characters, including English letters, numbers, punctuation marks, Latin letters, etc.

(2)$str

$str is the string that needs to be converted.

2. Example demonstration: Convert GBK encoded string to UTF-8 encoded string

The following is an example demonstration to show how to use the iconv function. In the code below, we convert a GBK-encoded Chinese character string into a UTF-8-encoded string.

//原始字符串為GBK編碼
$str = "中文";

//使用iconv函數(shù)轉(zhuǎn)換為UTF-8編碼
$str = iconv("GBK", "UTF-8", $str);

//輸出轉(zhuǎn)換后的字符串
echo $str;

After executing the above code, the page will output "Chinese", which means the original GBK-encoded Chinese character string is successfully converted into a UTF-8-encoded string.

3. Example Demonstration: Convert UTF-8 encoded string to GBK encoded string

Let’s use an example demonstration to show another way to use the iconv function. In the code below, we convert a UTF-8 encoded string to a GBK encoded string.

//原始字符串為UTF-8編碼
$str = "中文";

//使用iconv函數(shù)轉(zhuǎn)換為GBK編碼
$str = iconv("UTF-8", "GBK", $str);

//輸出轉(zhuǎn)換后的字符串
echo $str;

After executing the above code, the page will also output "Chinese", which means the original UTF-8 encoded string is successfully converted into a GBK encoded string.

4. Under what circumstances is it necessary to use the iconv function

In the actual development process, it is often necessary to convert between different encoding formats. For example, when we obtain data from the database, it may happen that the original data is encoded in GBK, but the front-end display page needs to be displayed in UTF-8 encoding. At this time, we need to use the iconv function to perform encoding conversion.

In addition, the iconv function also needs to be used in the following situations:

• When receiving a POST or GET request, since the encoding used by the client is not necessarily the same as that of the server, this You need to use the iconv function for encoding conversion.
• When reading local files, since different files may use different encoding methods, you also need to use the iconv function for encoding conversion.

To sum up, the iconv function is a very important character encoding processing function in PHP, which can easily achieve conversion between different encoding formats. In the actual development process, if you encounter a situation that requires encoding conversion, you can try to use the iconv function to complete it.

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