Added PHP Substring Function to Guide. (#33826)

* Added PHP Substring Function to Guide.

* Added PHP Substring Function to Guide.

* Fixed typo

guide/english/php/substring/index.md

@@ -0,0 +1,44 @@
+---
+title: subtring
+---
+
+## Substring Function in PHP
+
+The Substring function in PHP returns a portion of the string, specified by two parameters, the start and the length.
+
+
+## Syntax
+
+The substring function is used like any other function in php, and uses the subtr() syntax.
+
+
+```
+<?php
+
+subtr( $string, $start, $length);
+
+
+```
+
+
+## Example
+
+Below is an example of how you could use the substring function in a real world situation:
+
+```
+<?php
+
+$apple = 'Apple';
+$alphabet = 'abcdefghijklmnopqrstuvwxyz';
+
+substr($apple, 0, 5);  				// Apple;
+substr($apple, 0, 3);  				// App;
+substr($apple, 3, 2);  				// le;
+substr($alphabet, 0, 26);  			// abcdefghijklmnopqrstuvwxyz;
+substr($alphabet, 12, 6);  			// mnopqr;
+
+```
+
+## Additional Info
+
+For more information, please see [PHP: Substring](http://php.net/manual/en/function.substr.php)