Analysis on usage of substr function string interception in PHP

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 - Starts at the first character in the string

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:

<?php
 echo substr("Welcome to www.jb51.net!",0); //原样输出，不截取
 echo "
";
 echo substr("Welcome to www.jb51.net!",4,14); //从第4个字符开始连续截取14个字符
 echo "
";
 echo substr("Welcome to www.jb51.net!",-4,4); //从倒数第4个开始截取4个字符
 echo "
";
 echo substr("Welcome to www.jb51.net!",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:

Welcome to www.jb51.net!
ome to www.jb5
net!
Welcome to www.jb51.

I hope this article will be helpful to everyone PHP programming helps.

The above has introduced the analysis of the usage of substr function string interception in PHP, including various aspects. I hope it will be helpful to friends who are interested in PHP tutorials.