Question

我有一个这样的数组：


array (0 => 
  array (
    'id' => '20110209172713',
    'Date' => '2011-02-09',
    'Weight' => '200',
  ),
  1 => 
  array (
    'id' => '20110209172747',
    'Date' => '2011-02-09',
    'Weight' => '180',
  ),
  2 => 
  array (
    'id' => '20110209172827',
    'Date' => '2011-02-09',
    'Weight' => '175',
  ),
  3 => 
  array (
    'id' => '20110211204433',
    'Date' => '2011-02-11',
    'Weight' => '195',
  ),
)

我需要提取最小和最大权重值。在这个例子中

$ min_value = 175

$ max_value = 200

有关如何执行此操作的任何帮助？谢谢！

Answer 1

选项1.首先映射数组以获取这些数字（而不是完整的详细信息）：

$numbers = array_column($array, 'weight')

然后你得到最小和最大：

$min = min($numbers);
$max = max($numbers);

选项2.（仅当您没有PHP 5.5时。）与选项1相同，但要采用值，请使用array_map：

$numbers = array_map(function($details) {
  return $details['Weight'];
}, $array);

~~选项3。~~

选项4.如果您只需要最小或最大值，array_reduce()可能会更快：

$min = array_reduce($array, function($min, $details) {
  return min($min, $details['weight']);
}, PHP_INT_MAX);

这会有更多min() s，但它们非常快。 PHP_INT_MAX从高处开始，越来越低。您可以对$max执行相同的操作，但是您可以从0或-PHP_INT_MAX开始。

Answer 2

foreach ($array as $k => $v) {
  $tArray[$k] = $v['Weight'];
}
$min_value = min($tArray);
$max_value = max($tArray);

Answer 3

对于使用PHP 5.5+的人来说，使用array_column可以轻松完成。不再需要那些丑陋的array_maps了。

如何获得最大值：

$highest_weight = max(array_column($details, 'Weight'));

如何获得最小值

$lowest_weight = min(array_column($details, 'Weight'));

Answer 4

值得注意的是，上述两种解决方案都使用数组形式的额外存储（其中前两个，第二个使用一个数组），然后使用“额外存储”数组找到min和max。虽然这在真正的编程世界中是可以接受的（谁给出了两个关于“额外”存储的东西？）但它会让你在编程101中获得“C”。

只需两个额外的内存插槽即可轻松解决查找最小值和最大值的问题

$first = intval($input[0]['Weight']);
$min = $first ;
$max = $first ;

foreach($input as $data) {
    $weight = intval($data['Weight']);

    if($weight <= $min ) {
        $min =  $weight ;
    }

    if($weight > $max ) {
        $max =  $weight ;
    }

}

echo " min = $min and max = $max \n " ;

Answer 5

$num = array (0 => array ('id' => '20110209172713', 'Date' => '2011-02-09', 'Weight' => '200'),
          1 => array ('id' => '20110209172747', 'Date' => '2011-02-09', 'Weight' => '180'),
          2 => array ('id' => '20110209172827', 'Date' => '2011-02-09', 'Weight' => '175'),
          3 => array ('id' => '20110211204433', 'Date' => '2011-02-11', 'Weight' => '195'));

    foreach($num as $key => $val)   
    {                       
        $weight[] = $val['Weight'];
    }

     echo max($weight);
     echo min($weight);

Answer 6

<?php 
$array = array (0 => 
  array (
    'id' => '20110209172713',
    'Date' => '2011-02-09',
    'Weight' => '200',
  ),
  1 => 
  array (
    'id' => '20110209172747',
    'Date' => '2011-02-09',
    'Weight' => '180',
  ),
  2 => 
  array (
    'id' => '20110209172827',
    'Date' => '2011-02-09',
    'Weight' => '175',
  ),
  3 => 
  array (
    'id' => '20110211204433',
    'Date' => '2011-02-11',
    'Weight' => '195',
  ),
);

foreach ($array as $key => $value) {
  $result[$key] = $value['Weight'];
}
$min = min($result);
$max = max($result);

echo " The array in Minnumum number :".$min."<br/>";
echo " The array in Maximum  number :".$max."<br/>";
?>

Answer 7

$Location_Category_array = array(5,50,7,6,1,7,7,30,50,50,50,40,50,9,9,11,2,2,2,2,2,11,21,21,1,12,1,5);

asort($Location_Category_array);
$count=array_count_values($Location_Category_array);//Counts the values in the array, returns associatve array
        print_r($count);
        $maxsize = 0;
        $maxvalue = 0;
        foreach($count as $a=>$y){
            echo "<br/>".$a."=".$y;
            if($y>=$maxvalue){
                $maxvalue = $y;
                if($a>$maxsize){
                    $maxsize = $a;
                }
            }
        }

    echo "<br/>max = ".$maxsize;

Answer 8

如果不使用min或max等预定义函数，那该怎么办？

$arr = [4,5,6,7,8,2,9,1];
$val = $arr[0];
$n = count($arr);

for($i=1;$i<$n;$i++) {
if($val<$arr[$i]) {
    $val = $val;        
} else {
    $val = $arr[$i];
}
}
print($val);

＆GT;

Answer 9

从数组中快速打印五个最大和最小数字，而不使用php中的排序数组： -

<?php  

$array = explode(',',"78, 60, 62, 68, 71, 68, 73, 85, 66, 64, 76, 63, 81, 76, 73,  
68, 72, 73, 75, 65, 74, 63, 67, 65, 64, 68, 73, 75, 79, 73");  
$t=0;  
$l=count($array);  
foreach($array as $v)  
{  
 $t += $v;  
}  
 $avg= $t/$l;  
 echo "average Temperature is : ".$avg."  ";   


echo "<br>List of seven highest temperatsures :-"; 
$m[0]= max($array); 
for($i=1; $i <7 ; $i++)
{ 
$m[$i]=max(array_diff($array,$m));
}
foreach ($m as $key => $value) {
    echo "  ".$value; 
}
echo "<br> List of seven lowest temperatures : ";
$mi[0]= min($array); 
for($i=1; $i <7 ; $i++)
{ 
$mi[$i]=min(array_diff($array,$mi));
}

foreach ($mi as $key => $value) {
    echo "  ".$value; 
}
?>

获取PHP数组中的最小值和最大值

9 个答案: