w3resource

PHP: substr() function

Description

The substr() function used to cut a part of a string from a string, starting at a specified position.

Version:

(PHP 4 and above)

Syntax:

substr(string_name, start_pos, length_to_cut)

Parameters:

Name Description Required /
Optional		 Type
string_name The input string. Required String
start_pos Refers to the position of the string to start cutting.
A positive number : Start at the specified position in the string.
A negative number : Start at a specified position from the end of the string.		 Required Integer
length_to_cut Length of the string to cut from the main string.
A positive number : Start at the specified position in the string.
A negative number : Start at a specified position from the end of the string.		 Optional Integer

Return value:

Returns the extracted part of string and false when failure.

Value Type: String.

Pictorial Presentation

string_substr

Example - 1: 

<?php
$string1="Welcome to w3resource.com";
echo $string1;
echo '<br>';
echo substr($string1,1);
echo '<br>';
echo substr($string1,1,5);
echo '<br>';
echo substr($string1,0,10);
echo '<br>';
echo substr($string1,-1,1);
echo '<br>';
?>

Output: 

Welcome to w3resource.com
elcome to w3resource.com
elcom
Welcome   to
m

View the example in the browser

Example - 2 : 

<?php
$string1="Welcome to w3resource.com";
echo $string1;
echo '<br>';
echo substr($string1,0,-1);
echo '<br>';
echo substr($string1,3,-3);
echo '<br>';
echo substr($string1,4,-4);
echo '<br>';
echo substr($string1,-3,-2);
echo '<br>';
?>

Output :

Welcome to w3resource.com
Welcome to w3resource.co
come to   w3resource.
ome to w3resource
c

View the example in the browser

Example - 3 :

<?php
$string1="Welcome to w3resource.com";
echo $string1;
echo '<br>';
echo substr($string1,-1);
echo '<br>';
echo substr($string1,-4);
echo '<br>';
echo substr($string1,-5,1);
?>

Output :

Welcome to w3resource.com
m
.com
e

View the example in the browser

See also

PHP Function Reference

Previous: substr_replace
Next: trim



PHP: Tips of the Day

Get the full URL in PHP

Have a look at $_SERVER['REQUEST_URI'], i.e.

Example:

$actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

(Note that the double quoted string syntax is perfectly correct)

If you want to support both HTTP and HTTPS, you can use

$actual_link = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? "https" : "http") . "://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

Editor's note: using this code has security implications. The client can set HTTP_HOST and REQUEST_URI to any arbitrary value it wants.

Ref : https://bit.ly/2ZYItNJ