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Hàm strripos() trong PHP

Hướng dẫn cách sử dụng hàm strripos() trong lập trình PHP

Tác dụng của hàm strripos()

The strripos() function finds the position of the last occurrence of a string inside another string.

This function is case-insensitive. For case-sensitive searches, use the strrpos() function.

The following table summarizes the technical details of this function.

Return Value: Returns the position of the last occurrence of a string within another string, or FALSE if the string was not found. Remember that string positions start at 0, not 1.
Version: PHP 5+

Syntax

The basic syntax of the strripos() function is given with:

strripos(string, search, start);

The following example shows the strripos() function in action.

<?php
// Sample strings
$str = "The woodpeckers live in the woods.";
$substr = "The wood";

// Performing search
echo strripos($str, $substr);
?>

Parameters

The strripos() function accepts the following parameters.

Parameter Description
string Required. Specifies the string to search in.
search Required. Specifies the string to search for.
start Optional. Specifies the position in the string to start searching from. If a negative value is specified, the search is performed right to left skipping the last start number of characters of the string and searching for the first occurrence of the search string.

More Examples

Here're some more examples showing how strripos() function actually works:

The following example uses the start parameter to perform searching.

<?php
// Performing search
echo strripos("The woodpeckers live in the woods.", "wood", 3); 
?>

In the following example the start parameter is set to a negative value.

<?php
// Performing search
echo strripos("The woodpeckers live in the woods.", "wood", -10);
?>

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