At least in PHP 4.4.0, array_key_exists is inconsistently sensitive to different data types. For example, if your first argument is a double and the keys in your array are integers, array_key_exists will always return false. If you then cast the first argument to an integer, or even to a string, then you can successfully match. I haven't tested all the possibilities, to see when it'll tolerate different data types and when it won't, so the easiest and safest solution is to cast your first argument to match the data type of the keys.
array_key_exists
说明
bool array_key_exists ( mixed key, array search )array_key_exists() 在给定的 key 存在于数组中时返回 TRUE。key 可以是任何能作为数组索引的值。array_key_exists() 也可用于对象。
注: 在 PHP 4.0.6 中本函数名为 key_exists()。
参见 isset()，array_keys() 和 in_array()。
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User Contributed Notes
Mike Toppa
04-Aug-2006 01:43
04-Aug-2006 01:43
ncurtis at cenicola-helvin dot com
09-Jul-2006 06:25
09-Jul-2006 06:25
array_key_exists() does not check values in the key i wrote this function to check if a key in an array has a empty value as corresponds to values that return true for empty() an redirects to a page if specified otherwise returns false
<?php
function keysExists($array, $startingIndex, $redirectPage) {
if(is_array($array)) {
if (!empty($startingIndex)) {
for ($i = 0; $i < $startingIndex; $i++) {
next($array);
}
}
while(list($key, $value) = each($array)) {
if (empty($value)) {
if (!empty($redirectPage)) {
header("Location: $redirectPage");
} else {
return FALSE;
}
}
}
} else {
return FALSE;
}
}
?>
email me and let me no if you found this useful!
marzetti.marco at gmail.com
06-Jul-2006 05:44
06-Jul-2006 05:44
Returns the keys in $arr matching $pattern in a regex
<?php
function regex_array_keys ( &$arr, $pattern ) {
$results[] = false;
if( !is_array( $arr ) )
return false;
while( !is_null( $key = key( $arr ) ) ) {
if( preg_match( $pattern, $key ) )
$results[] = $key;
next($arr);
}
reset( $arr );
return $results;
}
?>
josh at nitrotech dot org
29-May-2006 09:24
29-May-2006 09:24
Here is a simple method for searching nested arrays.
<?php
function in_array_multi_key($needle, $haystack)
{
// mutidimentional search for in_array function
// only matches the key, values don't count.
if ( array_key_exists($needle, $haystack) )
{
return TRUE;
}
foreach ( $haystack as $key => $value )
{
if ( is_array($value) )
{
$work = in_array_multi_key($needle, $value);
if ( $work )
{
return TRUE;
}
}
}
return FALSE;
}
?>
(Code from www.nitrotech.org)
09-May-2006 11:44
property_exists() does the same thing for object properties.