Each of the arguments required by the function, must be in the array supplied in the third argument to iterator_apply. You can use references too. Example:
<?php
function translate_to(string $target_language, Iterator $words, array $dictionaries) {
$language = ucfirst($target_language);
$dictionary = $dictionaries[$target_language] ?? 'not found';
if ($dictionary === 'not found') {
echo "Not found dictionary for {$language}\n";
return;
}
echo "English words translated to {$language}\n";
$not_found = [];
iterator_apply($words, function($words, $dictionary, &$not_found){
$english_word = $words->current();
$translated_word = $dictionary[$english_word] ?? '';
if ($translated_word !== '') {
echo "{$english_word} translates to {$translated_word}\n";
} else {
$not_found[] = $english_word;
}
return true;
}, array($words, $dictionary, &$not_found));
echo "\nNot found words:\n" . implode("\n", $not_found) . "\n";
}
$dictionaries = [
'nahuatl' => [
'one' => 'Ze',
'two' => 'Ome',
'three' => 'Yei',
'four' => 'Nahui',
],
];
$iterator = new \ArrayIterator(array('one', 'two', 'three', 'four', 'gasoil'));
translate_to('nahuatl', $iterator, $dictionaries);
?>
English words translated to Nahuatl
one translates to Ze
two translates to Ome
three translates to Yei
four translates to Nahui
Not found words:
gasoil
iterator_apply
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
iterator_apply — 为迭代器中每个元素调用函数
说明
循环迭代每个元素时调用函数。
参数
-
iterator -
要迭代的迭代对象。
-
callback -
每个元素要调用的回调函数。此函数仅接收指定的
args，因此默认为 null。如果count($args) === 3，则回调函数是三个参数。注意: 为了遍历
iterator，此函数必须返回true。 -
args -
参数 array；
args的每个元素都会作为单独的参数传递给回调callback。
返回值
返回已迭代的元素个数。
示例
示例 #1 iterator_apply() 示例
<?php
function print_caps(Iterator $iterator) {
echo strtoupper($iterator->current()) . "\n";
return TRUE;
}
$it = new ArrayIterator(array("Apples", "Bananas", "Cherries"));
iterator_apply($it, "print_caps", array($it));
?>以上示例会输出：
APPLES BANANAS CHERRIES
add a note
User Contributed Notes 3 notes
tezcatl at fedoraproject dot org ¶
6 years ago
tezcatl at fedoraproject dot org ¶
6 years ago
Be aware of the proper methods to iterate the specific Iterator you are consuming, as the implementation of the method could vary its behaviour.
For example, unlike the ArrayIterator, you can't iterate on a SplDoubleLinkedList with current() without using next() on every iteration (and then, only would iterate if you return true at the end of the callable. It is far easier then with LinkedLists use a while($it->valid()) { $it->current(); $it->next(); }
Let's see:
<?php
$ll = new \SplDoublyLinkedList();
$ll->push('ze');
$ll->push('ome');
$ll->push('yei');
$ll->push('nahui');
$ll->rewind();
$iterations_done = iterator_apply($ll, function(Iterator $it) {
echo implode("\t=>", [
$it->key(),
$it->current(),
ucfirst($it->current())
]),"\n";
return true;
}, array($ll));
echo "Did iterate {$iterations_done} times \n";
$ll->rewind();
$iterations_done = iterator_apply($ll, function(Iterator $it) {
echo implode("\t=>", [
$it->key(),
$it->current(),
ucfirst($it->current())
]),"\n";
$it->next();
return true;
}, array($ll));
echo "Did iterate {$iterations_done} times \n";
$ll->setIteratorMode(SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_DELETE);
var_dump($ll->count());
foreach($ll as $key => $val) {
echo "{$key}\t",ucfirst($val),"\n";
}
var_dump($ll->count());
?>
Output:
0 =>ze =>Ze
0 =>ze =>Ze
0 =>ze =>Ze
0 =>ze =>Ze
Did iterate 4 times
0 =>ze =>Ze
1 =>ome =>Ome
2 =>yei =>Yei
3 =>nahui =>Nahui
Did iterate 4 times
int(4)
0 Ze
0 Ome
0 Yei
0 Nahui
int(0)
ycgambo at outlook dot com ¶
7 years ago
$args is an array and each of its elements are passed to the callback as separate arguments.
so this is the right way to get args:
<?php
$ai = new ArrayIterator(range(0, 2));
iterator_apply($ai, function() {
var_dump(func_get_args()); // use this func
return true;
}, array(1, 2));
?>
output:
array(2) {
[0] =>
int(1)
[1] =>
int(2)
}
array(2) {
[0] =>
int(1)
[1] =>
int(2)
}
array(2) {
[0] =>
int(1)
[1] =>
int(2)
}
--------------------------------------------------
or list each args:
<?php
$ai = new ArrayIterator(range(0, 2));
iterator_apply($ai, function($arg1, $arg2, $arg3) {
var_dump([$arg1, $arg2, $arg3]);
return true;
}, array(1, 2));
?>
same output.
