substr function string interception usage analysis _php techniques in PHP

This article illustrates the use of substr function string interception in PHP. Share to everyone for your reference, specific as follows:

The SUBSTR function in PHP is defined as follows:

SUBSTR (String,start,length)

The parameter description is as follows:

String required. A string that stipulates the part to return.

Start
Necessary. Specify where to start the string.
Positive number-starts at the specified position of the string
Negative number-starts at the specified position starting at the end of the string
0-Starts at the first character in the string

Length

Optional. Specify the length of the string to be returned. The default is until the end of the string.
Positive number-The length returned from the position where the start parameter is located
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);//output as is, do not intercept
 echo "<br>";
 echo substr ("Welcome to www.jb51.net!", 4,14); 14 characters are continuously intercepted from the 4th character
 echo "<br>";
 echo substr ("Welcome to www.jb51.net!", -4,4); From the penultimate 4th intercept 4 characters
 echo "<br>";
 echo substr ("Welcome to www.jb51.net!", 0,-4); Intercept from the first character, intercept to the penultimate 4th character
?>

The results of the operation are as follows:

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

I hope this article will help you with the PHP program design.