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Ce document utilise Manuel du site Web PHP chinois Libérer
(PHP 4 >= 4.0.5, PHP 5, PHP 7)
array_search — 在数组中搜索给定的值,如果成功则返回相应的键名
$needle
, array $haystack
[, bool $strict
= false
] )
在 haystack
中搜索
needle
参数。
needle
搜索的值。
Note:
如果
needle
是字符串,则比较以区分大小写的方式进行。
haystack
这个数组。
strict
如果可选的第三个参数 strict
为 TRUE
,则
array_search() 将在 haystack
中检查完全相同的元素。
这意味着同样检查 haystack
里 needle
的 类型,并且对象需是同一个实例。
如果找到了 needle
则返回它的键,否则返回 FALSE
。
如果 needle
在
haystack
中出现不止一次,则返回第一个匹配的键。要返回所有匹配值的键,应该用
array_keys() 加上可选参数
search_value
来代替。
此函数可能返回布尔值
FALSE
,但也可能返回等同于 FALSE
的非布尔值。请阅读 布尔类型章节以获取更多信息。应使用
===
运算符来测试此函数的返回值。
版本 | 说明 |
---|---|
5.3.0 |
As with all internal PHP functions as of 5.3.0,
array_search() returns NULL if invalid parameters
are passed to it.
|
4.2.0 |
在 PHP 4.2.0 之前, array_search() 在失败时返回
NULL 而不是 FALSE 。
|
Example #1 array_search() 例子
<?php
$array = array( 0 => 'blue' , 1 => 'red' , 2 => 'green' , 3 => 'red' );
$key = array_search ( 'green' , $array ); // $key = 2;
$key = array_search ( 'red' , $array ); // $key = 1;
?>
[#1] maciej at speccode dot com [2015-08-18 05:58:56]
FYI, remember that strict mode is something that might save you hours.
If you're searching for a string and you have a "true" boolean on the way - you will get it as result (first occurrence). Example below:
<?php
$arr = [
'foo' => 'bar',
'abc' => 'def',
'bool' => true,
'target' => 'xyz'
];
var_dump( array_search( 'xyz', $arr ) ); //bool
var_dump( array_search( 'xyz', $arr, true ) ); //target
?>
[#2] raat1979 at gmail dot com [2015-07-09 09:15:29]
I needed to search for sequences of values in an array,
In addition I needed to search from a given offset.
Unfortunately for neither I could find a function to do this.
This Is how I did it,
The function returns the position where position 0 of the needle matches
<?php
function array_find($needle,array $haystack,$offset=0,$length=null,$strict = false,$returnAll = false,$resultsBeforeStart=false){
if(count($haystack)===0) return false; //empty haystack never contain a needle
if($offset>count($haystack)) return false; //looking higher then the top of the haystack will never find anything
if($offset!==0) $haystack = array_slice($haystack, $offset, $length , true);
if(is_array($needle) && count($needle)===1) $needle = array_pop($needle);
if(!is_array($needle)){
$matches = array_keys($haystack,$needle,$strict);
}else{
$needleKeys = array_keys($needle); //becomes array(0=>1,1=>4);
$needlePositions = array();
foreach($needleKeys as $key=>$pos){
$needlePartPositions = array_keys($haystack,$needle[$pos],$strict);
if(count($needlePartPositions)===0) return false;
foreach($needlePartPositions as $fkey=>$fval){
//we correct the found fosition based on the position in the needle, as a result
//all matches set at the match position relative to start of needle
$matchStart = $fval-$pos;
if($matchStart >= 0 && ($matchStart>=$offset || $resultsBeforeStart)){
if(!isset($needlePositions[$matchStart])){
$needlePositions[$matchStart] = 1;
}else{
$needlePositions[$matchStart]++;
}
}
}
}
$matches = array_keys($needlePositions,count($needle),true); //find all matches for which the position count matches the needle count
}
if($matches === false) return false;
if(count($matches)===0) return false;
if($returnAll) return $matches;
return array_shift($matches);
}
$needle1 = array(1=>'D',4=>'G');
$needle2 = array('D','E');
$needle3 = array(1=>'D',2=>'E');
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
$haystack = array('A','B','C','D','E','F','G','H','I','J','H','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
//26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 55 46 47 48 49 50 51
'A','B','C','D','E','F','G','H','I','J','H','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
//52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
'A','B','C','D','E', 'G','H','I','J','H','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z');
var_dump(array_find($needle1,$haystack,0,null,true,true));
var_dump(array_find($needle1,$haystack,29,null,true,true));
var_dump(array_find($needle1,$haystack,29,null,true,true,true));
var_dump(array_find($needle2,$haystack,0,null,true,true));
var_dump(array_find($needle2,$haystack,55,null,true,false));
var_dump(array_find($needle2,$haystack,56,null,true,false,true));
?>
// D is at position 3 and 29 but they are matched at position 1 of the needle
// position 0 of the needle would therefore be at 2 and 28
array(2) {
[0]=> int(2)
[1]=> int(28)
}
//no match after position 29 that is after the start position
bool(false)
// items in the needle are matched at position 29 but needle starts at 1, $resultsBeforeStart was true so this one is included
array(1) {
[0]=> int(28)
}
// D,E found at 3 positions
array(3) {
[0]=> int(3)
[1]=> int(29)
[2]=> int(55)
}
//search for D,E starting at position 55 finds 1 match
int(55)
//search for D,E starting at position 56 finds NO matches, even if $resultsBeforeStart is set to true because the needle starts at position 0
bool(false)
[#3] superbueno at gmail dot com [2015-04-30 23:19:49]
Like many others, === failed for a 0-indexed occurrence. My solution was to test if an integer returned:
if ( is_int ( array_search($value, $array) ) ) return true;
[#4] emanuel dot tavares at connix dot com dot br [2015-03-19 15:47:33]
Hi!
I've tried to use array_search to fill an array with registers from a database seach with this:
$registros = 0;
while ( $row = $this->result->fetch_array() )
{
if ( !array_search($row[cd_subsecao], $this->listaSecoes) )
$registros = array_push($this->listaSecoes, $row[cd_subsecao]);
}
But the result was:
Array
(
[0] => obr
[1] => obr
[2] => obr
[3] => a10
[4] => obr
[5] => obr
[6] => obr
)
It was caused by because the first element has repetitions.
Then I've tried to substitute the !array_search.... for array_search(...) == FALSE, but it didn't worked too.
The solution was to use the "===":
$registros = 0;
while ( $row = $this->result->fetch_array() )
{
if ( array_search($row[cd_subsecao], $this->listaSecoes) === FALSE)
$registros = array_push($this->listaSecoes, $row[cd_subsecao]);
}
It returned:
Array
(
[0] => obr
[1] => a10
)
[#5] xfoxawy at gmail dot com [2015-02-02 11:30:01]
in (PHP 5 >= 5.5.0) you don't have to write your own function to search through a multi dimensional array
ex :
$userdb=Array
(
(0) => Array
(
(uid) => '100',
(name) => 'Sandra Shush',
(url) => 'urlof100'
),
(1) => Array
(
(uid) => '5465',
(name) => 'Stefanie Mcmohn',
(pic_square) => 'urlof100'
),
(2) => Array
(
(uid) => '40489',
(name) => 'Michael',
(pic_square) => 'urlof40489'
)
);
simply u can use this
$key = array_search(40489, array_column($userdb, 'uid'));
[#6] nan at designpromote dot co dot uk [2015-01-16 16:45:23]
$array = ['a', 'b', 'c'];
$key = array_search('a', $array); //$key = 0
if ($key)
{
//even a element is found in array, but if (0) means false
//...
}
//the correct way
if (false !== $key)
{
//....
}
It's what the document stated "may also return a non-Boolean value which evaluates to FALSE."
[#7] podarokua at gmail dot com [2014-10-17 04:45:04]
Here is a method for getting all keys, containing searched value, recursively
private function ras($needle, $haystack) {
$keys = array();
foreach ($haystack as $key => $value) {
if ($needle === $value OR (is_array($value) && $this->ras(
$needle,
$value
) !== FALSE)
) {
$keys[] = $key;
}
}
if (!empty($keys)) {
return $keys;
}
return FALSE;
}
[#8] marvin dot petker at borntocreate dot de [2014-09-05 16:08:56]
Be aware of using array_search() in conditional statements.
$foo = array("one", "two");
if( $key = array_search("one", $foo) ){
echo "Found";
}
else{
echo "Not found";
}
//Ouput: Not found
"Not found" will be outputted beacause the returned key is 0 and that will be interpreted as false in conditional statements.
[#9] dk at danilok dot com [2014-08-21 18:26:22]
I needed a way to return the value of a single specific key, thus:
<?php
function recursive_return_array_value_by_key($needle, $haystack){
$return = false;
foreach($haystack as $key => $val){
if(is_array($val)){
$return = recursive_return_array_value_by_key($needle, $val);
}
else if($needle === $key){
return "$val\n";
}
}
return $return;
}
?>
[#10] rAthur [2014-04-02 08:36:12]
If you're not running an older version of PHP (many servers are still on PHP 5.3), you can replace the function by this :
<?php
function s($needle,$array)
{
foreach($array as $key => $value)
if ($value==$needle)
return $key;
return false;
}
echo s( 'c', array('a', 'b', 'c', 'd') ); // returns 2
echo s( 'f', array('a', 'b', 'c', 'd') ); // returns false
?>
[#11] rAthur [2014-04-02 08:35:56]
If you're not running an older version of PHP (many servers are still on PHP 5.3), you can replace the function by this :
<?php
function s($needle,$array)
{
foreach($array as $key => $value)
if ($value==$needle)
return $key;
return false;
}
echo s( 'c', array('a', 'b', 'c', 'd') ); // returns 2
echo s( 'f', array('a', 'b', 'c', 'd') ); // returns false
?>
[#12] rAthur [2014-04-02 08:35:33]
If you're not running an older version of PHP (many servers are still on PHP 5.3), you can replace the function by this :
<?php
function s($needle,$array)
{
foreach($array as $key => $value)
if ($value==$needle)
return $key;
return false;
}
echo s( 'c', array('a', 'b', 'c', 'd') ); // returns 2
echo s( 'f', array('a', 'b', 'c', 'd') ); // returns false
?>
[#13] sunelbe at gmail dot com [2012-09-21 12:19:03]
hey i have a easy multidimensional array search function
<?php
function search($array, $key, $value)
{
$results = array();
if (is_array($array))
{
if (isset($array[$key]) && $array[$key] == $value)
$results[] = $array;
foreach ($array as $subarray)
$results = array_merge($results, search($subarray, $key, $value));
}
return $results;
}
?>
[#14] sneskid at hotmail dot com [2012-03-15 20:50:56]
I had an array of arrays and needed to find the key of an element by comparing actual reference.
Beware that even with strict equality (===) php will equate arrays via their elements recursively, not by a simple internal pointer check as with class objects. The === can be slow for massive arrays and also crash if they contain circular references.
This function performs reference sniffing in order to return the key for an element that is exactly a reference of needle.
<?php
function array_ref_search(&$v, array &$s)
{
if(is_object($v)){ return array_search($v, $s, true); }
foreach($s as $rK => &$rV)
{ // reference sniff
$tV = $v;
if( ($rV === ($v = 1)) && ($rV === ($v = 0)) ){
$v = $tV; return $rK; }
$v = $tV;
}
return false; // use null for php < 4.2.0
}
$list = array();
$list['A'] = &$valA; $list['B'] = &$valB;
$valA = 1; $valB = 1;
echo 'array_ref_search: ', array_ref_search($valB, $list), '</br>'; // key 'B'
echo 'array_search: ', array_search($valB, $list, true), '</br>'; // key 'A'
$valA = array(1,2,3); $valB = array(1,2,3);
echo 'array_ref_search: ', array_ref_search($valB, $list), '</br>'; // key 'B'
echo 'array_search: ', array_search($valB, $list, true), '</br>'; // key 'A' because ($valA === $valB) is true by elements
$valB[] = &$valB; // circular reference
echo 'array_ref_search: ', array_ref_search($valB, $list), '</br>'; // key 'B'
echo 'array_search: ', array_search($valB, $list, true), '</br>'; // crash because ($valB === $valB) causes infinite loop
?>
[#15] revoke [2011-10-11 04:12:37]
Better solution of multidimensional searching.
<?php
function multidimensional_search($parents, $searched) {
if (empty($searched) || empty($parents)) {
return false;
}
foreach ($parents as $key => $value) {
$exists = true;
foreach ($searched as $skey => $svalue) {
$exists = ($exists && IsSet($parents[$key][$skey]) && $parents[$key][$skey] == $svalue);
}
if($exists){ return $key; }
}
return false;
}
$parents = array();
$parents[] = array('date'=>1320883200, 'uid'=>3);
$parents[] = array('date'=>1320883200, 'uid'=>5);
$parents[] = array('date'=>1318204800, 'uid'=>5);
echo multidimensional_search($parents, array('date'=>1320883200, 'uid'=>5)); // 1
?>
[#16] stooshie at gmail dot com [2011-10-06 02:51:09]
Example of a recursive binary search that returns the index rather than boolean.
<?php
// returns the index of needle in haystack
function binSearch($needle, $haystack)
{
// n is only needed if counting depth of search
global $n;
$n++;
// get the length of passed array
$l = count($haystack);
// if length is 0, problem
if($l <= 0)
{
return -1;
}
// get the mid element
$m = (($l+($l%2))/2);
// if mid >= length (e.g. l=1)
if($m >= $l)
{
$m = $m-1;
}
// get the indexed element to compare to the passed element and branch accordingly
$compare = $haystack[$m];
switch(true)
{
case($compare>$needle):
{
// recurse on the lower half
$new_haystack = array_slice($haystack, 0, $m);
$c = count($new_haystack);
$r = binSearch($needle, $new_haystack);
// return current index - (length of lower half - found index in lower half)
return $m - ($c - $r);
break;
}
case($compare<$needle):
{
// recurse on the upper half
$new_haystack = array_slice($haystack, $m, ($l-$m));
$c = count($new_haystack);
$r = binSearch($needle, $new_haystack);
// return current position + found index in upper half
return $m + $r;
break;
}
case($compare==$needle):
{
// found it, so return index
return $m;
break;
}
}
}
?>
[#17] Dave C [2011-09-27 13:18:57]
Here is a version of binary search that is done via recursion instead of iteration. Remember that your data needs to be presorted!
<?php
static function Bin_Search(&$needle, &$haystack, $start, $end) {
if($end < $start)
{
return false;
}
$mid = (int)(($end - $start) / 2) + $start;
if($haystack[$mid] > $needle)
{
return Bin_Search($needle, $haystack, $start, $mid - 1);
}
else if($haystack[$mid] < $needle)
{
return Bin_Search($needle, $haystack, $mid + 1, $end);
}
else
{
return true;
}
}
?>
[#18] stefano@takys dot it [2011-01-14 13:58:24]
for searching case insensitive better this:
<?php
array_search(strtolower($element),array_map('strtolower',$array));
?>
[#19] robert at robert-gonzalez dot com [2010-09-22 12:15:28]
I needed a way to find the parent hierarchy of a multidimensional array. Being the rogue that I am, I got to coding before searching the manual and came up with two little functions that will return a parent stack for a first find and a complete parent stack, similar in nature to the solution presented by jette at nerdgirl dot dk without all the extra stuff or use of eval(). ;)
<?php
function getParentStack($child, $stack) {
foreach ($stack as $k => $v) {
if (is_array($v)) {
// If the current element of the array is an array, recurse it and capture the return
$return = getParentStack($child, $v);
// If the return is an array, stack it and return it
if (is_array($return)) {
return array($k => $return);
}
} else {
// Since we are not on an array, compare directly
if ($v == $child) {
// And if we match, stack it and return it
return array($k => $child);
}
}
}
// Return false since there was nothing found
return false;
}
function getParentStackComplete($child, $stack) {
$return = array();
foreach ($stack as $k => $v) {
if (is_array($v)) {
// If the current element of the array is an array, recurse it
// and capture the return stack
$stack = getParentStackComplete($child, $v);
// If the return stack is an array, add it to the return
if (is_array($stack) && !empty($stack)) {
$return[$k] = $stack;
}
} else {
// Since we are not on an array, compare directly
if ($v == $child) {
// And if we match, stack it and return it
$return[$k] = $child;
}
}
}
// Return the stack
return empty($return) ? false: $return;
}
// TESTING
$array = array(
'balloon' => array(
'red' => array(1 => 'Love', 'Valentine', 'Heart',),
'green' => array(1 => 'Summertime', 'Hope',),
),
'ribbon' => array(
'yellow' => array(2 => 'Welcome',),
'red' => array(3 => 'Love', 'Love',),
),
);
$s = getParentStack('Love', $array);
$c = getParentStackComplete('Love', $array);
var_dump($s, $c);
?>
Output:
array
'balloon' =>
array
'red' =>
array
1 => string 'Love' (length=4)
array
'balloon' =>
array
'red' =>
array
1 => string 'Love' (length=4)
'ribbon' =>
array
'red' =>
array
3 => string 'Love' (length=4)
4 => string 'Love' (length=4)
[#20] hanan dot ali dot shaikh at googlemail dot com [2010-09-17 01:14:53]
In this code I write a code to find next and previous element of an array using current element of that array. Let suppose if we are in element 9 and have to access its next and previous element then this code be helpful for someone.
<?php
$myArray = array(4,5,7,9,10,11,13,19,25);
$currentElement = 9;
$firstElement = current($myArray);
$lastElement = $myArray[sizeof($myArray)-1];
$currentKey = array_search($currentElement, $myArray);
$currentValue = $myArray[$currentKey];
$previousValue = "";
$nextValue = "";
if($currentElement!=$lastElement){
$nextKey = $currentKey + 1;
$nextValue = $myArray[$nextKey];
}
if($currentElement!=$firstElement){
$previousKey = $currentKey - 1;
$previousValue = $myArray[$previousKey];
}
echo $previousValue."--".$currentValue."--".$nextValue;
?>
Thanks,
Hanan Ali
[#21] codeslinger at compsalot dot com [2009-10-02 00:22:12]
one thing to be very aware of is that array_search() will fail if the needle is a string and the array itself contains values that are mixture of numbers and strings. (or even a string that looks like a number)
The problem is that unless you specify "strict" the match is done using == and in that case any string will match a numeric value of zero which is not what you want.
-----
also, php can lookup an index pretty darn fast. for many scenarios, it is practical to maintain multiple arrays, one in which the index of the array is the search key and the normal array that contains the data.
<?php
$normal[$index] = array('key'=>$key, 'data'=>'foo');
$inverse[$key] = $index;
//very fast lookup, this beats any other kind of search
if (array_key_exists($key, $inverse))
{
$index = $inverse[$key];
return $normal[$index];
}
?>
[#22] temporal dot pl at gmail dot com [2009-09-04 15:57:04]
Sometimes you need to find a given value in a sorted array or - if not found - detect the place where it should be. After that you can for example split the array into two halves, the greater and the smaller one.
greenmr, dennis.decoene and php at celerondude had all posted very good binary search functions but these functions all return false if the needle was not found in the haystack. I've tweaked greenmr's code a little:
<?php
function Array_BinarySearch( $needle, $haystack, $comparator , &$probe )
{
$high = Count( $haystack ) -1;
$low = 0;
while ( $high >= $low )
{
$probe = Floor( ( $high + $low ) / 2 );
$comparison = $comparator( $haystack[$probe], $needle );
if ( $comparison < 0 )
{
$low = $probe +1;
}
elseif ( $comparison > 0 )
{
$high = $probe -1;
}
else
{
return true;
}
}
//The loop ended without a match
//Compensate for needle greater than highest haystack element
if($comparator($haystack[count($haystack)-1], $needle) < 0)
{
$probe = count($haystack);
}
return false;
}
?>
Now, the function returns true if it finds something and false otherwise. If a needle was found, then $probe will contain it's position. Otherwise, $probe will contain position of where the needle would be if it were there :). This is possible because we pass $probe by reference.
Example:
<?php
//ultra-simple comparator :)
function CompareNumbers($obj, $needle)
{
return $obj - $needle;
}
//use examples
$testArr = array(10, 20, 30, 40, 50);
$res = Array_BinarySearch(30, $testArr, 'CompareNumbers', $probe);
echo (int)$res.' '.$probe.'<br />';
//output is: 1 2 - found at position 2
$res = Array_BinarySearch(45, $testArr, 'CompareNumbers', $probe);
echo (int)$res.' '.$probe.'<br />';
//output is: 0 4 - not found, but it would be at position 4 (between 40 and 45)
$res = Array_BinarySearch(-3, $testArr, 'CompareNumbers', $probe);
echo (int)$res.' '.$probe.'<br />';
//output is: 0 0 - not found, but it would be at position 0 (before 10)
$res = Array_BinarySearch(300, $testArr, 'CompareNumbers', $probe);
echo (int)$res.' '.$probe.'<br />';
//output is: 0 5 - not found, but it would be at position 5 (after 50; note, that count($haystack) == 5)
?>
See original greenmr's note for additional details about usage of this binary search: http://php.net/manual/en/function.array-search.php#89413
[#23] Nguyen KimKha [2009-08-23 10:18:24]
You can remove some values from array, by using unset() and array_search().
<?php
$friends = array( 'Bob', 'Ann', 'Peter' ); // Two persons named 'Bob'
$find = 'Bob';
$key = array_search( $find, $friends ); // Find key of given value
if ($key != NULL || $key !== FALSE) {
unset($friends[$key]); // remove key from array
}
// Now, $friends = array( 'Ann', 'Peter');
?>
[#24] buddel [2009-06-08 08:13:23]
the recursive function by tony have a small bug. it failes when a key is 0
here is the corrected version of this helpful function:
<?php
function recursive_array_search($needle,$haystack) {
foreach($haystack as $key=>$value) {
$current_key=$key;
if($needle===$value OR (is_array($value) && recursive_array_search($needle,$value) !== false)) {
return $current_key;
}
}
return false;
}
?>
[#25] tony dot peter at wanadoo dot fr [2009-05-11 12:53:38]
A simple recursive array_search function :
<?php
function recursive_array_search($needle,$haystack) {
foreach($haystack as $key=>$value) {
$current_key=$key;
if($needle===$value OR (is_array($value) && recursive_array_search($needle,$value))) {
return $current_key;
}
}
return false;
}
?>
[#26] n-regen [2009-05-05 10:36:48]
If you only know a part of a value in an array and want to know the complete value, you can use the following function:
<?php
function array_find($needle, $haystack)
{
foreach ($haystack as $item)
{
if (strpos($item, $needle) !== FALSE)
{
return $item;
break;
}
}
}
?>
The function returns the complete first value of $haystack that contains $needle.
[#27] helenadeus at gmail dot com [2009-01-25 13:05:32]
I was trying to use array_search to retrieve all the values that match a given needle, but it turns out only the first match key is returned. I built this little function, which works just like array_search, but returns all the keys that match a given needle instead. The output is an array.
<?php
$haystack = array('a','b','a','b');
$needle = 'a';
print_r(array_search_all($needle, $haystack));
//Output will be
// Array
// (
// [0]=>1
// [1]=>3
// )
function array_search_all($needle, $haystack)
{#array_search_match($needle, $haystack) returns all the keys of the values that match $needle in $haystack
foreach ($haystack as $k=>$v) {
if($haystack[$k]==$needle){
$array[] = $k;
}
}
return ($array);
}
?>
[#28] azaozz, gmail [2008-12-20 17:23:43]
Expanding on the comment by hansen{}cointel.de:
When searching for a string and the array contains 0 (zero), the string is casted to (int) by the type-casting which is always 0 (perhaps the opposite is the proper behaviour, the array value 0 should have been casted to string). That produces unexpected results if strict comparison is not used:
<?php
$a = array(0, "str1", "str2", "str3");
echo "
str1 = ".array_search("str1", $a).",
str2 = ".array_search("str2", $a).",
str3 = ".array_search("str3", $a).",
str1 strict = ".array_search("str1", $a, true).",
str2 strict = ".array_search("str2", $a, true).",
str3 strict = ".array_search("str3", $a, true);
?>
This will return:
str1 = 0, str2 = 0, str3 = 0, str1 strict = 1, str2 strict = 2, str3 strict = 3
[#29] dcez at land dot ru [2008-04-30 13:15:51]
Simple way to get variable name by using array_search function:
<?php
function varname($var){
return (isset($var))? array_search($var, $GLOBALS) : false;
}
$boogie = 'tonight';
echo varname($boogie);
?>
[#30] andreas dot damm at maxmachine dot de [2008-04-03 16:07:52]
Combining syntax of array_search() and functionality of array_keys() to get all key=>value associations of an array with the given search-value:
<?php
function array_search_values( $m_needle, $a_haystack, $b_strict = false){
return array_intersect_key( $a_haystack, array_flip( array_keys( $a_haystack, $m_needle, $b_strict)));
}
?>
Usage:
<?php
$array1 = array( 'pre'=>'2', 1, 2, 3, '1', '2', '3', 'post'=>2);
print_r( array_search_values( '2', $array1));
print_r( array_search_values( '2', $array1, true));
print_r( array_search_values( 2, $array1, true));
?>
Will return:
array(4) {
["pre"] =>
string(1) "2"
[1] =>
int(2)
[4] =>
string(1) "2"
["post"] =>
int(2)
}
array(2) {
["pre"] =>
string(1) "2"
[4] =>
string(1) "2"
}
array(2) {
[1] =>
int(2)
["post"] =>
int(2)
}
[#31] kermes [at] thesevens [dot] net [2007-09-11 15:09:44]
A variation of previous searches that returns an array of keys that match the given value:
<?php
function array_ksearch($array, $str)
{
$result = array();
for($i = 0; $i < count($array); next($array), $i++)
if(strtolower(current($array)) == strtolower($str))
array_push($result, key($array);
return $result;
}
?>
Usage would be as follows:
<?php
$testArray = array('one' => 'test1', 'two' => 'test2', 'three' => 'test1', 'four' => 'test2', 'five' => 'test1');
print_r(array_ksearch($testArray, 'test1'));
?>
[#32] robertark at gmail dot com [2007-09-01 23:20:16]
A better array_isearch would be to store all results in an array, then return the KEYS stored in $found, such as:
<?php
function array_isearch($str, $array){
$found = array();
foreach ($array as $k => $v)
if (strtolower($v) == strtolower($str)) $found[] = $k;
return $found;
}
?>
To use, simply have an array to search from then search it, for example:
<?php
function array_isearch($str, $array) {
$found = array();
foreach($array as $k => $v)
if(strtolower($v) == strtolower($str)) $found[] = $k;
return $found;
}
$stored = "these are an array";
$stored = explode(" ", $stored);
$compare = array("these", "are", "some", "results", "stored", "in", "an", "array");
foreach($stored as $store) {
$results = array_isearch($store, $compare);
foreach($results as $key => $result)
echo "Key: ".$results[$key]."<br />Found: ".$compare[$result]."<br />";
}
?>
Hope this helps :-)
-Rob
[#33] php5 site builder [2007-05-23 10:14:46]
If you encounter a situation where condition test is failing on the result of either array_search or in_array, even when using "===" and "!==", make sure to set $strict = true in your array_search() or in_array() function call.
A situation such as :
$arTemp[0] = 1;
$arTemp[1] = 0;
$arTemp[2] = 3;
$arTemp[3] = 5;
$sTempTest = 'BLAH';
$bResult = in_array($sTempTest,$arTemp);
$bResult2 = array_search($sTempTest,$arTemp);
var_dump($bResult);
var_dump($bResult2);
will result in :
boolean true
int 1
Using :
$bResult = in_array($sTempTest,$arTemp,true);
$bResult2 = array_search($sTempTest,$arTemp,true);
will yield :
boolean false
boolean false
This is necessary in any instance where you have an array value equal to the integer zero. As soon as you put the zero in quotes or double quotes (a string), the evaluation works with in_array & array_search without the $strict parameter being set.
[#34] elvenone at gmail dot com [2007-01-27 05:10:01]
<?php
// Search an array in reverse order.
function array_reverse_search($value, $array) {
for($i = sizeof($array)-1; $i>=0; $i--) {
if ($array[$i] == $value) return $i;
}
return -1;
}
?>
[#35] dmitry dot polushkin at gmail dot com [2006-10-21 22:03:58]
To get the key of the found search value, use:
<?php
$a = array('a', 'b', 'c');
echo array_search(array_search('c', $a), array_keys($a));
?>
[#36] mark dot php at mhudson dot net [2006-09-11 17:49:01]
I was going to complain bitterly about array_search() using zero-based indexes, but then I realized I should be using in_array() instead.
// if ( isset( $_GET['table'] ) and array_search( $_GET['table'], $valid_tables) ) { // BAD: fails on first[0] element
// if ( isset( $_GET['table'] ) and ( FALSE !== array_search( $_GET['table'], $valid_tables) ) ) { OK: but wasteful and convoluted
if ( isset( $_GET['table'] ) and in_array( $_GET['table'], $valid_tables) ) { // BETTER
The essence is this: if you really want to know the location of an element in an array, then use array_search, else if you only want to know whether that element exists, then use in_array()
[#37] RichGC [2006-03-20 05:54:15]
To expand on previous comments, here are some examples of
where using array_search within an IF statement can go
wrong when you want to use the array key thats returned.
Take the following two arrays you wish to search:
<?php
$fruit_array = array("apple", "pear", "orange");
$fruit_array = array("a" => "apple", "b" => "pear", "c" => "orange");
if ($i = array_search("apple", $fruit_array))
//PROBLEM: the first array returns a key of 0 and IF treats it as FALSE
if (is_numeric($i = array_search("apple", $fruit_array)))
//PROBLEM: works on numeric keys of the first array but fails on the second
if ($i = is_numeric(array_search("apple", $fruit_array)))
//PROBLEM: using the above in the wrong order causes $i to always equal 1
if ($i = array_search("apple", $fruit_array) !== FALSE)
//PROBLEM: explicit with no extra brackets causes $i to always equal 1
if (($i = array_search("apple", $fruit_array)) !== FALSE)
//YES: works on both arrays returning their keys
?>
[#38] congaz at yahoo dot dk [2006-03-09 19:38:11]
Search a multi-dimensional array on keys!
-------------------------------------------
I needed to search dynamically in a multi-dimen array on keys. I came up with this little neat function. It is so amazingly simple, that I actually didn't think it would work - but it does...
mixed array_searchMultiOnKeys(array, array);
<?php
function array_searchMultiOnKeys($multiArray, $searchKeysArray) {
// Iterate through searchKeys, making $multiArray smaller and smaller.
foreach ($searchKeysArray as $keySearch) {
$multiArray = $multiArray[$keySearch];
$result = $multiArray;
}
// Check $result.
if (is_array($multiArray)) {
// An array was found at the end of the search. Return true.
$result = true;
}
else if ($result == '') {
// There was nothing found at the end of the search. Return false.
$result = false;
}
return $result;
// End of function,
}
// --- Test array_searchMultiOnKeys ---
$multiArray['webpages']['downloads']['music'] = 1;
$multiArray['webpages']['downloads']['pressmaterial'] = 5;
$multiArray['webpages']['links'] = 7;
array_searchMultiOnKeys($multiArray, array('webpages', 'links')); // returns 7.
array_searchMultiOnKeys($multiArray, array('webpages', 'downloads')); // returns true.
array_searchMultiOnKeys($multiArray, array('webpages', 'downloads', 'software')); // returns false.
?>
$multiArray / $searchKeysArray can be any size.
Happy hacking...
[#39] hansen{?}cointel.de [2006-02-08 18:26:19]
may be good to take note of PHP's mind-boggling 'fuzzy' (vulgo "magic type-casting") comparison features not only in using the results, but also in the search, too:
<?php
$a=array("a","b",0,"c","d");
echo "a: ".array_search("a",$a);
echo "b: ".array_search("b",$a);
echo "c: ".array_search("c",$a);
echo "d: ".array_search("d",$a);
echo "0: ".array_search("0",$a);
echo "x: ".array_search("x",$a);
echo "1: ".array_search("1",$a);
?>
will result in:
a: 0, b: 1, c: 2, d: 2, 0: 2, x: 2, 1: false
as from "c" on, the first match found in $a is "0", as any string compared to an int is automatically cast to (int)0.
[#40] F?lix Cloutier <felixcca at yahoo dot ca> [2004-10-22 05:01:21]
There is no function to count the occurences of needle in haystack, so I made my own one...
<?php
function array_match($needle, $haystack)
{
if( !is_array($haystack) ) return false;
$i = 0;
while( (in_array( $needle, $haystack )) != FALSE )
{
$i++;
$haystack[array_search($needle, $haystack)] = md5($needle);
reset($haystack);
}
return $i;
}
?>
I know it's a bit crappy, but don't ask me too much, I'm still only 13... ;)
[#41] dennis dot decoene at removthis dot moveit dot be [2004-01-17 10:41:26]
It has been said before: array_search is VERY slow. Everyone knows binary search is fast by design. Here is an implementation.
<?php
$arr=array(1,3,5,7,9,10,11,13);
$searchfor = 6;
echo binsearch($searchfor, $arr);
function binsearch($needle, $haystack)
{
$high = count($haystack);
$low = 0;
while ($high - $low > 1){
$probe = ($high + $low) / 2;
if ($haystack[$probe] < $needle){
$low = $probe;
}else{
$high = $probe;
}
}
if ($high == count($haystack) || $haystack[$high] != $needle) {
return false;
}else {
return $high;
}
}
?>
[#42] php at celerondude dot com [2003-11-12 03:07:34]
I think array_search uses serial search because they binary search function i wrote here seems to do a better job for records that are not always at the beginning of the array.
Here it is
<?php
function binarySearch ( $a, $t, $l, $r )
{
if($t<$a[$l]||$t>$a[$r])return NULL;
while ( $l < $r )
{
$m=intval($l+$r)/2;
if($a[$m]==$t)return $m;
elseif($t<$a[$m])$r=$m-1;
elseif($t>$a[$m])$l = $m + 1;
}
if($t==$a[$r])
return $r;
return NULL;
}
?>
usage:
binarySearch ( array, target, left range, right range );
if your array is a multidimensional array, simply change the comparison method. :)
[#43] cue at openxbox dot com [2003-06-09 19:50:20]
If you are using the result of array_search in a condition statement, make sure you use the === operator instead of == to test whether or not it found a match. Otherwise, searching through an array with numeric indicies will result in index 0 always getting evaluated as false/null. This nuance cost me a lot of time and sanity, so I hope this helps someone. In case you don't know what I'm talking about, here's an example:
<?php
$code = array("a", "b", "a", "c", "a", "b", "b"); // infamous abacabb mortal kombat code :-P
// this is WRONG
while (($key = array_search("a", $code)) != NULL)
{
// infinite loop, regardless of the unset
unset($code[$key]);
}
// this is _RIGHT_
while (($key = array_search("a", $code)) !== NULL)
{
// loop will terminate
unset($code[$key]);
}
?>
[#44] richard at richard-sumilang dot com [2003-04-16 03:59:21]
<?php
function array_search_r($needle, $haystack){
foreach($haystack as $value){
if(is_array($value))
$match=array_search_r($needle, $value);
if($value==$needle)
$match=1;
if($match)
return 1;
}
return 0;
}
?>
[#45] swbrown at ucsd dot edu [2002-05-02 01:18:50]
Be absolutely sure to check that your code that uses array_search now checks for 'false' too if you upgrade to PHP 4.2.0!
I was using array_search in my page authentication routines and this change had the fun side-effect of causing my code to always think a user had full permissions! It was letting anyone click through to our installation of phpMyAdmin. Not good indeed!