What is the strpos() function in PHP?

Overview

The strpos() method in PHP checks for the position of a string in another string. A string known as the ＄haystack value will be searched to find another value, ＄needle, inside it. For the strpos() method to evaluate as true and return the position of ＄needle in ＄haystack, the ＄needle value has to be a character or a set of characters that must be found in ＄haystack. Otherwise, it returns false.

Syntax

strpos($haystack,$needle, $offset)

• ＄haystack: This is the value that will contain the ＄needle value.

• ＄needle: This is a set of characters or a single character that may or may not be available in ＄haystack.

• ＄offset: This parameter is zero by default. It determines the position in ＄haystack from which the search of ＄needle should start. If the offset is negative, the search will start from the end of the ＄haystack.

Return value

• If the ＄needle is found in the ＄haystack, the return value will be the index position of the ＄needle in the ＄haystack.
• If the ＄needle is not found in the ＄haystack, the Boolean value false will be returned.

Code

In the code snippet below, the strpos() method gets the position of the same string in another string:

Explanation

• Line 2, 3, and 4: We declare the ＄searchWord, ＄stringVal1, and ＄stringVal2 variables.

• Line 6 and 7: We use the strpos() function to find the position of some substrings in them.

• Line 10, 11, and 12: We use the if statement to check what value is returned by the strpos() function, and if false executes the code in the block.

• Line 14, 15, and 16: We use the if statement to check what value is returned by the strpos() function. If it is not false, it executes the code in the block.