end
(PHP 4, PHP 5)
end — Установить внутренний указатель массива на его последний элемент
Описание
end() устанавливает внутренний указатель array на последний элемент и возвращает его значение.
Пример #1 Простой пример использования end()
<?php
$fruits = array('apple', 'banana', 'cranberry');
echo end($fruits); // cranberry
?>
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Коментарии
When adding an element to an array, it may be interesting to know with which key it was added. Just adding an element does not change the current position in the array, so calling key() won't return the correct key value; you must first position at end() of the array:
<?php
function array_add(&$array, $value) {
$array[] = $value; // add an element
end($array); // important!
return key($array);
}
?>
If you need to get a reference on the first or last element of an array, use these functions because reset() and end() only return you a copy that you cannot dereference directly:
<?php
function first(&$array) {
if (!is_array($array)) return &$array;
if (!count($array)) return null;
reset($array);
return &$array[key($array)];
}
function last(&$array) {
if (!is_array($array)) return &$array;
if (!count($array)) return null;
end($array);
return &$array[key($array)];
}
?>
Please note that from version 5.0.4 ==> 5.0.5 that this function now takes an array. This will possibly break some code for instance:
<?php
echo ">> ".end(array_keys(array('x' => 'y')))."\n";
?>
which will return "Fatal error: Only variables can be passed by reference" in version <= 5.0.4 but not in 5.0.5.
If you run into this problem with nested function calls, then an easy workaround is to assign the result from array_keys (or whatever function) to an intermediary variable:
<?php
$x = array_keys(array('x' => 'y'));
echo ">> ".end($x)."\n";
?>
This function returns the value at the end of the array, but you may sometimes be interested in the key at the end of the array, particularly when working with non integer indexed arrays:
<?php
// Returns the key at the end of the array
function endKey($array){
end($array);
return key($array);
}
?>
Usage example:
<?php
$a = array("one" => "apple", "two" => "orange", "three" => "pear");
echo endKey($a); // will output "three"
?>
Take note that end() does not recursively set your multiple dimension arrays' pointer to the end.
Take a look at the following:
<?php
// create the array for testing
$a = array();
$i = 0;
while($i++ < 3){
$a[] = array(dechex(crc32(mt_rand())),dechex(crc32('lol'.mt_rand())));
}
// show the array tree
echo '<pre>';var_dump($a);
// set the pointer of $a to the end
end($a);
// get the current element of $a
var_dump(current($a));
// get the current element of the current element of $a
var_dump(current(current($a)));
?>
You will notice that you probably get something like this:
array(3) {
[0]=>
array(2) {
[0]=>
string(8) "764d8d20"
[1]=>
string(8) "85ee186d"
}
[1]=>
array(2) {
[0]=>
string(8) "c8c72466"
[1]=>
string(8) "a0fdccb2"
}
[2]=>
array(2) {
[0]=>
string(8) "3463a31b"
[1]=>
string(8) "589f6b63"
}
}
array(2) {
[0]=>
string(8) "3463a31b"
[1]=>
string(8) "589f6b63"
}
string(8) "3463a31b"
The array elements' pointer are still at the first one as current. So do take note.
It's interesting to note that when creating an array with numeric keys in no particular order, end() will still only return the value that was the last one to be created. So, if you have something like this:
<?php
$a = array();
$a[1] = 1;
$a[0] = 0;
echo end($a);
?>
This will print "0".
If all you want is the last item of the array without affecting the internal array pointer just do the following:
<?php
function endc( $array ) { return end( $array ); }
$items = array( 'one', 'two', 'three' );
$lastItem = endc( $items ); // three
$current = current( $items ); // one
?>
This works because the parameter to the function is being sent as a copy, not as a reference to the original variable.
$filename = 'somefile.jpg';
php v5.4 does not support the following statement.
echo end(explode(".", $filename)); // return jpg string
instead you have to split into 2 statements
$file = explode(".", $filename);
echo end ($file);
I found that the function end() is the best for finding extensions on file name. This function cleans backslashes and takes the extension of a file.
<?php
private function extension($str){
$str=implode("",explode("\\",$str));
$str=explode(".",$str);
$str=strtolower(end($str));
return $str;
}
// EXAMPLE:
$file='name-Of_soMe.File.txt';
echo extension($file); // txt
?>
Very simple.
Attempting to get the value of a key from an empty array through end() will result in NULL instead of throwing an error or warning becuse end() on an empty array results in false:
<?php
$a = ['a' => ['hello' => 'a1','world' => 'a2'],
'b' => ['hello' => 'b1','world' => 'b2'],
'c' => ['hello' => 'c1','world' => 'c2']
];
$b = [];
var_dump(end($a)['hello']);
var_dump(end($b)['hello']);
var_dump(false['hello']);
?>
Results in:
string(2) "c1"
NULL
NULL
<?php
$A=[1];
print_r($A);
end($A[5]);
print_r($A);
?>
Array
(
[0] => 1
)
Array
(
[0] => 1
[5] =>
)