Let's talk about several methods of extracting the first few characters of a string in PHP

In PHP programming, string manipulation is one of the most common operations. Sometimes it is necessary to intercept the first few characters of a string to meet the needs of the program. This article will introduce how to get the first few characters of a string in PHP.

PHP language provides a variety of methods to intercept strings. The following are the three most commonly used methods:

1. Use the substr() function to extract substrings

substr ( string $string , int $start [, int $length ] ) : string

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

For example, to intercept the first 5 characters from the string "Hello World!", you can use the following code:

$string = "Hello World!";
$result = substr($string, 0, 5);
echo $result;

The running result is: Hello.

2. Use the mb_substr() function to extract the substring of a multi-byte encoded string

mb_substr ( string $str , int $start [, int $length = NULL [, string $encoding = mb_internal_encoding() ]] ) : string

Among them, $str is the string to be intercepted, $start is the starting position of interception, and $length is the length of interception (optional ), $encoding is the specified encoding method (optional).

For example, to intercept the first 3 characters from the Chinese string "Hello, world!", you can use the following code:

$string = "你好，世界！";
$result = mb_substr($string, 0, 3, 'utf-8');
echo $result;

The running result is: Hello.

3. Use the mb_strcut() function to intercept the string by the number of bytes

mb_strcut ( string $str , int $start [, int $length = NULL [, string $encoding = mb_internal_encoding() ]] ) : string

Among them, $str is the string to be intercepted, $start is the starting position of interception, $length is the length of interception (optional), $encoding The specified encoding (optional).

For example, to intercept the first 6 bytes from the Chinese string "Hello, world!", you can use the following code:

$string = "你好，世界！";
$result = mb_strcut($string, 0, 6, 'utf-8');
echo $result;

The running result is: Hello,.

Summary:

To get the first few characters of a string in PHP, you can use the substr() function, mb_substr() function and mb_strcut() function. These functions can be selected and used according to specific needs. However, it should be noted that when processing Chinese strings, you need to use the multi-byte encoding functions mb_substr() and mb_strcut(), otherwise garbled characters may occur.

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