Convert php string to utf8 encoded byte stream

In PHP, string is a very important data type. They are used to process text information, including retrieving data from databases, processing form data, reading files, etc.

When processing strings, character encoding issues are often involved. UTF-8 is a universal character encoding based on the Unicode character set and can represent almost all characters in the world. Therefore, UTF-8 encoded strings are widely used in international scenarios.

In PHP, due to historical reasons, the encoding used for strings is ISO-8859-1 encoding by default, and multi-byte characters cannot be processed correctly. Therefore, the string needs to be converted into a UTF-8 encoded byte stream to correctly handle multi-byte characters.

The following introduces several methods of converting strings into UTF-8 encoded byte streams.

1. Use the iconv() function

The iconv() function is a function built into PHP for string encoding conversion. A string can be converted from one encoding to another. Here, we can convert the ISO-8859-1 encoded string into a UTF-8 encoded byte stream.

Sample code:

$str = "中文";
$utf8 = iconv("ISO-8859-1", "UTF-8", $str);

The above code converts an ISO-8859-1 encoded string into a UTF-8 encoded byte stream. This method is relatively simple, but some character conversions may fail and additional error handling is required.

2. Use the mb_convert_encoding() function

The mb_convert_encoding() function is another function in PHP for string encoding conversion. It supports more character sets and can handle special characters in UTF-8 encoding, such as emoji expressions, etc.

Sample code:

$str = "中文";
$utf8 = mb_convert_encoding($str, "UTF-8", "ISO-8859-1");

The above code can convert an ISO-8859-1 encoded string into a UTF-8 encoded byte stream. This method is more stable than the iconv() function and can ensure that more characters are converted successfully.

3. Use the mb_substr() function

If you only need to convert a part of a string into a UTF-8 encoded byte stream, you can use the mb_substr() function. This function supports extracting a part of the string and converting the extracted string into the specified encoding.

Sample code:

$str = "中文 English";
$utf8 = mb_substr($str, 0, 6, "UTF-8");

The above code converts the first 6 characters of a string into a UTF-8 encoded byte stream. If the string that needs to be extracted contains a mixture of Chinese and English, you need to pay attention to the boundaries between Chinese and English.

Summary

The above three methods can convert a string into a UTF-8 encoded byte stream, among which the mb_convert_encoding() function has the best effect and can handle more characters. set and better error handling when conversion fails.

In actual development, if you need to process multi-language strings, it is recommended to use the mb_convert_encoding() function to perform encoding conversion to ensure correct processing results.

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