And if you want to know if there are any array elements in array before given key, you can use this function:
function any_array_keys_before($keyname, &$array) {
if (!is_array($array)) {
return false;
}
if (empty($keyname)) {
return false;
}
$set = false;
$count = 0;
foreach ($array as $key => $value) {
if ($set === false && $key != $keyname) {
$count ++;
} else if ($key == $keyname) {
$set = true;
}
}
return $count > 0 ? true : false;
}
next
说明
mixed next ( array &array )返回数组内部指针指向的下一个单元的值，或当没有更多单元时返回 FALSE。
next() 和 current() 的行为类似，只有一点区别，在返回值之前将内部指针向前移动一位。这意味着它返回的是下一个数组单元的值并将数组指针向前移动了一位。如果移动指针的结果是超出了数组单元的末端，则 next() 返回 FALSE。
| 警告 |
如果数组包含空的单元，或者单元的值是 0 则本函数碰到这些单元也返回 FALSE。要正确遍历可能含有空单元或者单元值为 0 的数组，参见 each() 函数。 |
add a note
User Contributed Notes
Sigmar
31-May-2006 06:02
31-May-2006 06:02
Sigmar
31-May-2006 05:52
31-May-2006 05:52
If you want to check, if there are some more elements in array after given key, you can use the following function:
function more_array_keys($keyname, &$array) {
if (!is_array($array)) {
return false;
}
if (empty($keyname)) {
return false;
}
$set = false;
$count = 0;
foreach ($array as $key => $value) {
if ($set === true) {
$count++;
}
if ($key == $keyname) {
$set = true;
}
}
return $count > 0 ? true : false;
}
tino at infeon dot com
13-May-2006 11:48
13-May-2006 11:48
this may be handy and i didnt know where else to post it.. i need a simple function to cycle through an array i eventually made it into a class so i could have multiple cycles.. if you like it or find it usefull please email me and let me know
class Cycle
{
var $position;
var $dataArray;
var $dataArrayCount;
function Cycle()
{
$this->dataArray = func_get_args();
$this->dataArrayCount = count($this->dataArray);
}
function Display()
{
$this->position = (!isset($this->position) || $this->position >= ($this->dataArrayCount - 1)) ? 0 : $this->position += 1;
return $this->dataArray[$this->position];
}
}
$bgColor = new Cycle('#000000', '#FFFFFF', '#FF0000');
echo $bgcolor->Display();
//returns #000000
echo $bgcolor->Display();
//returns #FFFFFF
echo $bgcolor->Display();
//returns #FF0000
echo $bgcolor->Display();
//returns #000000
brentimus
29-Apr-2005 01:10
29-Apr-2005 01:10
Papipo's function below is usefull in concept but does not work.
"Since you do not pass the array by reference, its pointer is only moved inside the function."
This is true, but the array you are manipulating in your has_next() function will have it's pointer set to the first element, not the same position as the original array. What you want to do is pass the array to the has_next() function via reference. While in the has_next() function, make a copy of the array to work on. Find out the current pointer position of the original array and set the pointer on the working copy of the array to the same element. Then you may test to see if the array has a "next" element.
Try the followig insetad:
<?php
function has_next(&$array)
{
$A_work=$array; //$A_work is a copy of $array but with its internal pointer set to the first element.
$PTR=current($array);
array_set_pointer($A_work, $PTR);
if(is_array($A_work))
{
if(next($A_work)===false)
return false;
else
return true;
}
else
return false;
}
function array_set_pointer(&$array, $value)
{
reset($array);
while($val=current($array))
{
if($val==$value)
break;
next($array);
}
}
?>
papipo's gmail account
13-Oct-2004 04:47
13-Oct-2004 04:47
I need to know if an array has more items, but without moving array's internail pointer. Thats is, a has_next() function:
<?php
function has_next($array) {
if (is_array($array)) {
if (next($array) === false) {
return false;
} else {
return true;
}
} else {
return false;
}
}
$array = array('fruit', 'melon');
if (has_next($array)) {
echo next($array);
}
// prints 'melon'
?>
Since you do not pass the array by reference, its pointer is only moved inside the function.
Hope that helps.
lukasz at karapuda dot com
19-Aug-2004 01:06
19-Aug-2004 01:06
This function will return the previous,next neighbors of an array entry within an associative array. If the specified $key points to the last or first element of the array, the first or last keys of the array will be returned consecutively. This is an improved version of the same function posted earlier.
<?php
function array_neighbor($arr, $key)
{
$keys = array_keys($arr);
$keyIndexes = array_flip($keys);
$return = array();
if (isset($keys[$keyIndexes[$key]-1])) {
$return[] = $keys[$keyIndexes[$key]-1];
}
else {
$return[] = $keys[sizeof($keys)-1];
}
if (isset($keys[$keyIndexes[$key]+1])) {
$return[] = $keys[$keyIndexes[$key]+1];
}
else {
$return[] = $keys[0];
}
return $return;
}
?>
court shrock
21-May-2004 07:36
21-May-2004 07:36
This code returns neighbors of the specified key. The result will be empty if it doesn't have any neighbors. My approach was to use the order of keys to determine neighbors, which is differnet from just getting the next/previous element in an array. Feel free to point out stupidities :)
<?php
function array_neighbor($arr, $key)
{
krsort($arr);
$keys = array_keys($arr);
$keyIndexes = array_flip($keys);
$return = array();
if (isset($keys[$keyIndexes[$key]-1]))
$return[] = $keys[$keyIndexes[$key]-1];
if (isset($keys[$keyIndexes[$key]+1]))
$return[] = $keys[$keyIndexes[$key]+1];
return $return;
}
?>
bm at ANTISPAM dot solidwave dot com
17-Apr-2004 12:49
17-Apr-2004 12:49
Take care when replacing code using reset()/next() with code using foreach as foreach does not update the array's internal pointer. This means you cannot, say, use next() to skip an element in foreach loop, or use current() within a function to get a reference to the current element. You probably have code depending on this internal pointer and replacing it will be more work than you anticipated.
See http://www.php.net/foreach