ArrayIterator::append()
(PHP 5,PHP 7)
Append an element
说明
public ArrayIterator::append(mixed $value) : void
Appends value as the last element.
Warning本函数还未编写文档,仅有参数列表。
参数
- $value
The value to append.
返回值
没有返回值。
注释
Note:This method cannot be called when theArrayIteratorrefers to anobject.
参见
- ArrayIterator::next() Move to next entry
As ArrayIterator is not a real list the implementation of "append" is a little bit confusing me. When using "append" I expected the new value at the postion "last element index + 1". This will not happen when you unset elements before. It seems like indexes once they're used are blacklisted end never used again, even if they're unset. Like suggested in http://www.php.net/manual/de/arrayiterator.offsetset.php#106775 ArrayIterator::append uses ArrayIterator::offsetSet with empty index parameter. So I've this two workarounds to get "append" to work like I want: <?php class myArrayIterator extends ArrayIterator { public function offsetSet($offset, $value) { if (is_null($offset)) { // offset == null when it's called by ArrayIterator::append $offset = $this->generateOffset(); // do it in a separate method } parent::offsetSet($offset, $value); // call the native implementation with an index $this->ksort(); // sort it to avoid confusion when it gets dumped or iterated } protected function generateOffset() { $offset = count($this); // take count as offset as it should be lastKey+1 while ($this->offsetExists($offset)) { // is it really empty? $offset++; // try the next one until there's an empty one } return $offset; } } class mySaveArrayIterator extends myArrayIterator { protected function generateOffset() { $offset = 0; // expect zero is the first possible key while ($this->offsetExists($offset)) { // try every key until there's an empty one $offset++; } return $offset; } } $data = array('foo', 'bar', 'baz'); $array = new ArrayIterator($data); $myArray = new myArrayIterator($data); $mySaveArray = new mySaveArrayIterator($data); // remove the last element $array ->offsetUnset(2); $myArray ->offsetUnset(2); $mySaveArray->offsetUnset(2); // append an element $array ->append('foobar'); $myArray ->append('foobar'); $mySaveArray->append('foobar'); // check the position of the new element print_r($array); print_r($myArray); print_r($mySaveArray); // remove some element $array ->offsetUnset(1); $myArray ->offsetUnset(1); $mySaveArray->offsetUnset(1); // again append an element $array ->append('foobarbaz'); $myArray ->append('foobarbaz'); $mySaveArray->append('foobarbaz'); // check the position of the new element print_r($array); print_r($myArray); print_r($mySaveArray); ?> Output: ArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [1] => bar [3] => foobar ) ) myArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [1] => bar [2] => foobar ) ) mySaveArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [1] => bar [2] => foobar ) ) ArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [3] => foobar [4] => foobarbaz ) ) myArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [2] => foobar [3] => foobarbaz ) ) mySaveArrayIterator Object ( [storage:ArrayIterator:private] => Array ( [0] => foo [1] => foobarbaz [2] => foobar ) ) This helped me to treat the ArrayIterator as a list with valid indexes in a serial manner.
we can append values after the given array,the index is begin from 0, for example: <?php $b = array('name'=>'mengzhi','age'=>'22','city'=>'shanghai'); $a = new ArrayIterator($b); $a->append(array('home'=>'china','work'=>'developer')); var_dump($a); ?> then output: object(ArrayIterator)#1 (1) { ["storage":"ArrayIterator":private]=> array(4) { ["name"]=> string(7) "mengzhi" ["age"]=> string(2) "12" ["city"]=> string(8) "shanghai" [0]=> array(2) { ["home"]=> string(5) "china" ["work"]=> string(9) "developer" } } }