PHPsubstr function string interception usage analysis

php substr is a functional function developed based on the php language that can return a part of a string. The example in this article describes the usage of substr function string interception in PHP. Share it with everyone for your reference, the details are as follows:

The substr function in PHP is defined as follows:

substr(string,start,length)

The parameter description is as follows:

string required. Specifies a part of the string to be returned.

start

Required. Specifies where in the string to begin.

Positive number - starts at the specified position in the string

Negative number - starts at the specified position from the end of the string

0 - first in the string Starts at character

length

Optional. Specifies the length of the returned string. The default is until the end of the string.

Positive number - the length returned from the position of the start parameter

Negative number - the length returned from the end of the string

The sample code is as follows:

?123456789 <?php  echo substr("Welcome to www.php.cn!",0);
//原样输出，不截取  echo "<br>";  echo substr("Welcome to www.php.cn!",4,14); 
//从第4个字符开始连续截取14个字符  echo "<br>";  echo substr("Welcome to www.php.cn!",-4,4);
//从倒数第4个开始截取4个字符  echo "<br>";  echo substr("Welcome to www.php.cn!",0,-4); 
//从第一个字符开始截取,截取到倒数第4个字符 ?>

The running results are as follows:

?1234 Welcome to www.php.cn!welcome tophp.cn! Welcome to www.php.cn.

Although the article is very short, it can teach You have a knowledge point, I hope this article will be helpful to everyone in PHP programming.

The method of substr_count() function in PHP to obtain the number of occurrences of a substring, phpsubstr_count_PHP tutorial

Usage analysis of substr function string interception in PHP, phpsubstr

The method of substr_count() function in PHP to obtain the number of occurrences of a substring, phpsubstr_count

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