php intercepts garbled Chinese characters

In recent years, PHP, as a general scripting language, has been widely used in the field of Web development. However, when processing text containing Chinese characters, PHP encoding problems have always troubled developers. Especially when PHP intercepts Chinese characters, problems such as garbled characters often occur.

So, how to solve the problem of PHP intercepting garbled Chinese characters?

1. Problems with PHP Chinese encoding

First of all, we need to understand the basic knowledge of PHP Chinese encoding. The character set supported by PHP by default is ISO-8859-1, which is Latin-1. In China, we usually use UTF-8 or GBK encoding.

Therefore, when processing text containing Chinese characters in PHP, you need to ensure that the encoding method of the string is consistent with the encoding method in the editor or database used, otherwise it is easy to intercept and garbled Chinese characters.

2. How to intercept Chinese characters in PHP

1. substr function

The substr function is the most basic string interception function in PHP, which can intercept one character part of the string.

The syntax of this function is as follows:

substr(string $string, int $start, int $length)

Among them, $string is the string to be intercepted, $ start is the starting position of interception, counting from 0; $length is the length of interception.

For example, to intercept "Hello" in the string "Hello World", you can use the following code:

$str = "Hello World";
echo substr($str, 0, 5);

However, when we intercept a string containing Chinese characters, garbled characters will appear.

2. mb_substr function

In order to solve the problem of the substr function intercepting garbled Chinese characters, PHP provides the mb_substr function.

The mb_substr function is a function in the multibyte string function library, which can handle multi-byte characters, that is, Chinese characters, Japanese and other characters.

The syntax of this function is as follows:

mb_substr(string $string, int $start, int $length, string $encoding)

Among them, $string is the value to be intercepted String, $start is the starting position of interception, counting from 0; $length is the length of interception; $encoding is the encoding method of string.

For example, to intercept the string "Hello World" containing Chinese characters, you can use the following code:

$str = "Hello World";
echo mb_substr($str, 0, 2, 'utf-8');

This code will output "Hello".

When using the mb_substr function, you need to pay attention to the encoding method of the string to be consistent with $encoding, otherwise there will still be a problem of intercepting garbled Chinese characters.

3. How to intercept the length of Chinese strings in PHP

In addition to intercepting Chinese characters, sometimes we also need to calculate the length of Chinese strings in PHP. When dealing with the length of Chinese strings, you also need to pay attention to the issue of character encoding.

1. strlen function

The strlen function is the most basic string length function in PHP, which can calculate the length of a string. However, when processing strings containing Chinese characters, the strlen function cannot accurately calculate the length of the characters.

For example, to calculate the length of the string "Hello World", you can use the following code:

$str = "Hello World";
echo strlen($str);

This code will output 9 instead of the correct 4. This is because the strlen function cannot correctly handle multi-byte characters such as Chinese characters.

2. mb_strlen function

In order to solve the problem that the strlen function cannot handle the length of Chinese strings, PHP provides the mb_strlen function.

The mb_strlen function is also a function in the multibyte string function library and can handle multi-byte characters, that is, Chinese characters, Japanese and other characters.

The syntax of this function is as follows:

mb_strlen(string $string, string $encoding)

Among them, $string is the string whose length is to be calculated; $encoding is the character String encoding method.

For example, to calculate the length of the string "Hello World", you can use the following code:

$str = "Hello World";
echo mb_strlen($str, ' utf-8');

This code will output 4, correctly calculating the length of the string.

In short, when processing strings containing Chinese characters in PHP, you need to pay attention to character encoding issues. For the need to intercept multi-byte characters such as Chinese characters, it is recommended to use the mb_substr function, and for the need to calculate the length of Chinese strings, the mb_strlen function should be used.

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