Rechercher une fonction PHP

strrpos

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(PHP 4, PHP 5, PHP 7)

strrpos — Find the position of the last occurrence of a substring in a string

Description

strrpos ( string $haystack , mixed $needle [, int $offset = 0 ] ) : int

Find the numeric position of the last occurrence of needle in the haystack string.

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Parameters

haystack

The string to search in.

needle

If needle is not a string, it is converted to an integer and applied as the ordinal value of a character. This behavior is deprecated as of PHP 7.3.0, and relying on it is highly discouraged. Depending on the intended behavior, the needle should either be explicitly cast to string, or an explicit call to chr() should be performed.

offset

If zero or positive, the search is performed left to right skipping the first offset bytes of the haystack.

If negative, the search is performed right to left skipping the last offset bytes of the haystack and searching for the first occurrence of needle.

Note:

This is effectively looking for the last occurrence of needle before the last offset bytes.

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Return Values

Returns the position where the needle exists relative to the beginning of the haystack string (independent of search direction or offset).

Note: String positions start at 0, and not 1.

Returns FALSE if the needle was not found.

Warning

This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

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Examples

Example #1 Checking if a needle is in the haystack

It is easy to mistake the return values for "character found at position 0" and "character not found". Here's how to detect the difference:

<?php

$pos = strrpos($mystring, "b");
if ($pos === false) { // note: three equal signs
    // not found...
}

?>

Example #2 Searching with offsets

<?php
$foo = "0123456789a123456789b123456789c";

// Looking for '0' from the 0th byte (from the beginning)
var_dump(strrpos($foo, '0', 0));

// Looking for '0' from the 1st byte (after byte "0")
var_dump(strrpos($foo, '0', 1));

// Looking for '7' from the 21th byte (after byte 20)
var_dump(strrpos($foo, '7', 20));

// Looking for '7' from the 29th byte (after byte 28)
var_dump(strrpos($foo, '7', 28));

// Looking for '7' right to left from the 5th byte from the end
var_dump(strrpos($foo, '7', -5));

// Looking for 'c' right to left from the 2nd byte from the end
var_dump(strrpos($foo, 'c', -2));

// Looking for '9c' right to left from the 2nd byte from the end
var_dump(strrpos($foo, '9c', -2));
?>

The above example will output:

int(0)
bool(false)
int(27)
bool(false)
int(17)
bool(false)
int(29)

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See Also

  • strpos() - Find the position of the first occurrence of a substring in a string
  • stripos() - Find the position of the first occurrence of a case-insensitive substring in a string
  • strripos() - Find the position of the last occurrence of a case-insensitive substring in a string
  • strrchr() - Find the last occurrence of a character in a string
  • substr() - Return part of a string

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Document created the 30/01/2003, last modified the 26/10/2018
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