Learn how to use PHP strstr & strpos Functions

Introduction

If you want to find position of first occurrence of specified string (needle) in another string (haystack) or wants to fetch remaining part from the starting of needle up to the end or vice versa, then, PHP has provided an inbuilt solution of such tasks/problems with two functions listed below, which are members of "PHP String Functions" in PHP.

  1. "strstr()" PHP function And,
  2. "strpos()" PHP function.

Basic Terms Explained Here

  • Needle - A word or smaller string,
  • haystack - A bigger string i.e. a group of words like a sentence.

List of Contents

  1. Usage and Description of both PHP Functions,
  2. Syntax of Both Functions,
  3. Parameters of Both Function,
  4. Return Types and Values,
  5. Practical Examples Showing the Usage of both PHP Functions.

Php strstr() & strpos() functions
Php strstr() & strpos() functions

Usages and Descriptions

PHP strstr Function

  1. Returns the part of bigger string (haystack) from the first occurrence of specified string (needle) up to the end.
  2. Returns the part of bigger string (haystack) upto the first occurrence of specified string (needle) from starting (if third parameter (which is optional) sets to true).

PHP strpos Function

  • This PHP function returns the numeric position of specified string (needle) in bigger string (haystack).

Syntax of strstr and strpos PHP functions

Here, Below are the syntax's of both functions. parameters inside square brackets are optional and keywords (identifiers) used before parameters are indicating the data type of each parameter that this functions will accept.

<?php

//PHP strstr() function syntax
string strstr ( string $haystack , mixed $needle [, bool $before_needle = false ] );

//PHP strpos() function syntax
int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] );

?>

Parameters of Both PHP Functions

Parameters of PHP strstr Function

  1. "$haystack" - A string on which search action is to be performed.
  2. "$needle" - Searchable String i.e. A string that is going to be searched.
  3. "$before_needle" - This is optional parameter whose default value is "false". If set to "true", the part before first occurrence of needle in haystack will be returned by strstr function.

Parameters of PHP strpos Function

Well, First two parameters of this function are same as first two in "strstr" function. Third parameter is different and is explained below.

"$offset" - The optional offset parameter allows you to specify which character in haystack to start searching. The position returned is still relative to the beginning of haystack. In simple words "From where to start searching".

Return Types and Values

Return Values of strstr function

  • If Needle Found : This function will return portion of haystack which may either be portion before first occurrence or portion after first occurrence of needle, which will be of string data type.
  • If Needle Not Found : This function will return "false" which is of Boolean data type.

Return Values of strpos function

  • If Needle Found : This function will return position of needle in numeric form which is of integer data type.
  • If Needle Not Found : This function will return "false" which is of Boolean data type.

Examples of strstr and strpos PHP Functions

Here, Below are the Examples showing the usage of both strstr and strpos PHP functions.

Example of strstr Function

<?php

$myEmail  = 'myname@example.com';
$domainNAME = strstr($myEmail, '@');
echo $domainNAME; 
// Output will be @example.com

$myNAME = strstr($myEmail, '@', true); // As of PHP 5.3.0
echo $myNAME; 
// Output will be myname
?> 

Example of strpos Function

<?php
echo strpos("My Unexpected String!","ex");

//This will Output
//5 

echo strpos("My Unexpected String!","my");
//This will Output 
//0 

?> 

Resolve Your Queries

If you have any questions regarding this function or about any section of this tutorial, then, you are kindly invited to ask it in comments section below.

Thanks for Reading.

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