Question

PHP array查询key的问题

这样一个array，怎样知道同一个value的key的个数Array ( [0] => 5 [1] => 5 [2] => 4 [3] => 4 [4] => 3 [5] => 3 [6] => 2 [7] => 2 [8] => 1 [9] => 1 [10] => 1 [11] => 1 [12] => 1 )

Answer 1

//返回是一维数组 return array('value' => 个数)

function getArrKeyCount($arr)
{
$arrKeyNum = array();
foreach($arr as $val)
{
$arrKeyNum[$val] = isset($arrKeyNum[$val]) ? $arrKeyNum[$val]+1 : 1;
}
return $arrKeyNum;
}

$arr = array(5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 1, 1, 1);
$result = getArrKeyCount($arr);
//此例$result = array('5' => 2, '4' => 2, '3' => 2, '2' => 2, '1' => 5);

Answer 2

你找到几个相同值不就找到几个不同的Key值了吗

Answer 3

function howmany($value, $array){
foreach($array as $each){
if($each==$value){
$resultnum++;
}
}
return $resultnum;
}

Answer 4

count($array)或者sizeof($array)