(PHP 4, PHP 5, PHP 7)
each — Return the current key and value pair from an array and advance the array cursor
Ця функція ЗАСТАРІЛА, починаючи з PHP 7.2.0, та ВИЛУЧЕНА в PHP 8.0.0. Вкрай не рекомендується на неї покладатися.
Return the current key and value pair from an array and advance the array cursor.
After each() has executed, the array cursor will be left on the next element of the array, or past the last element if it hits the end of the array. You have to use reset() if you want to traverse the array again using each.
arrayThe input array.
Returns the current key and value pair from the array
array. This pair is returned in a four-element
array, with the keys 0, 1,
key, and value. Elements
0 and key contain the key name of
the array element, and 1 and value
contain the data.
If the internal pointer for the array points past the end of the
array contents, each() returns
false.
Приклад #1 each() examples
<?php
$foo = array("bob", "fred", "jussi", "jouni", "egon", "marliese");
$bar = each($foo);
print_r($bar);
?>$bar now contains the following key/value pairs:
Array
(
[1] => bob
[value] => bob
[0] => 0
[key] => 0
)
<?php
$foo = array("Robert" => "Bob", "Seppo" => "Sepi");
$bar = each($foo);
print_r($bar);
?>$bar now contains the following key/value pairs:
Array
(
[1] => Bob
[value] => Bob
[0] => Robert
[key] => Robert
)
each() is typically used in conjunction with list() to traverse an array, here's an example:
Приклад #2 Traversing an array with each()
<?php
$fruit = array('a' => 'apple', 'b' => 'banana', 'c' => 'cranberry');
reset($fruit);
while (list($key, $val) = each($fruit)) {
echo "$key => $val\n";
}
?>Поданий вище приклад виведе:
a => apple b => banana c => cranberry
Because assigning an array to another variable resets the original array's pointer, our example above would cause an endless loop had we assigned $fruit to another variable inside the loop.
each() will also accept objects, but may return unexpected results. It's therefore not recommended to iterate though object properties with each().
Following the obsolescence of the each() function, here is a way to correct your source codes:
If you use each() in a while loop like this:
while (list($Key,$Value)=@each($Array)){
....
}
you have to replace with
foreach ($Array as $Key => $Value){
....
}
In the same minds.
while (list(,$Value)=@each($Array)){
....
}
will become
foreach ($Array as $Value){
....
}each was deprecated because it exposed too much of the internal implementation details, blocking language development. ("We can't do X because it would break each().")
https://wiki.php.net/rfc/deprecations_php_7_2#each
If you want an array pointer, maintain it yourself. Probably a good idea anyway, because then it's visible in the code.Use foreach instead of while, list and each. Foreach is:
- easier to read
- faster
- not influenced by the array pointer, so it does not need reset().
It works like this:
<?php
$arr = array('foo', 'bar');
foreach ($arr as $value) {
echo "The value is $value.";
}
$arr = array('key' => 'value', 'foo' => 'bar');
foreach ($arr as $key => $value) {
echo "Key: $key, value: $value";
}
?>Hello, since each() and list() often "betray" very old applications, I simply recommend not to use them anymore.
If you want to assign variables based on an associative array,
Replace this:
while(list ($key, $value) = each ($my_array)) {
$$key = $value;
}
with this:
foreach ($my_array as $key => $value) {
$$key = $value;
}Rector has an automated fix ('ListEachRector') to migrate away from `each()`:
https://github.com/rectorphp/rector/blob/master/docs/AllRectorsOverview.md#listeachrector
If you look at the code example you'll see this is even quite simple to do by hand.