Question

嗨我想找到x和y的最小值和最大值我怎么能找到这个min和max函数不能正常工作

$dataPoints = array(
 array('x' => 2343, 'y' => 4322),
  array('x' => 103, 'y' => 303 ),
  array('x' => 2345,'y' => 2321 ),
  array('x' => 310, 'y' => 2044 ),
  array('x' => 173, 'y' => 793 ),
  array('x' => 456, 'y' => 2675),
  array('x' => 24, 'y' => 819 ));

Answer 1

我认为你必须编写自己的函数：

<?php  
    function max_with_key($array, $key) {
        if (!is_array($array) || count($array) == 0) return false;
        $max = $array[0][$key];
        foreach($array as $a) {
            if($a[$key] > $max) {
                $max = $a[$key];
            }
        }
        return $max;
    }


    $dataPoints = array(
     array('x' => 2343, 'y' => 4322),
      array('x' => 103, 'y' => 303 ),
      array('x' => 2345,'y' => 2321 ),
      array('x' => 310, 'y' => 2044 ),
      array('x' => 173, 'y' => 793 ),
      array('x' => 456, 'y' => 2675),
      array('x' => 24, 'y' => 819 ));

    $max_x = max_with_key($dataPoints, 'x');  //2343
    $max_y = max_with_key($dataPoints, 'y');  //4322
?>

Answer 2

尝试这样的事情：

foreach($dataPoints as $point) {
    if (!isset($x) || $point['x'] > $x) {
        $x = $point['x'];
    }
    if (!isset($y) || $point['y'] > $y) {
        $y = $point['y'];
    }
}

Answer 3

您可以使用PHP的array_column()（PHP 5＆gt; = 5.5.0）：

$min_x = min( array_column( $dataPoints, 'x' ) );
$min_y = min( array_column( $dataPoints, 'y' ) );
$max_x = max( array_column( $dataPoints, 'x' ) );
$max_x = max( array_column( $dataPoints, 'y' ) );

Answer 4

我是下划线图书馆的粉丝

http://brianhaveri.github.com/Underscore.php/#max

不是原生的，但会让您免于编写自己的功能，以及许多其他功能：）

哦，它变成了单行！

示例：

include_once 'underscore.php';

$dataPoints = array(
    array('x' => 2343, 'y' => 4322),
    array('x' => 103, 'y' => 303 ),
    array('x' => 2345,'y' => 2321 ),
    array('x' => 310, 'y' => 2044 ),
    array('x' => 173, 'y' => 793 ),
    array('x' => 456, 'y' => 2675),
    array('x' => 24, 'y' => 819 )
);


__::max($dataPoints, function($item) { return $item['x']; });    // array('x' => 2345,'y' => 2321 )
__::min($dataPoints, function($item) { return $item['y']; });    // array('x' => 103, 'y' => 303 )

Answer 5

//to find max use rsort() & for min :sort()
//Below will return you the max 
$dataPoints = array(
     array('x' => 2343, 'y' => 4322),
      array('x' => 103, 'y' => 7303 ),
      array('x' => 2345,'y' => 2321 ),
      array('x' => 310, 'y' => 2044 ),
      array('x' => 173, 'y' => 793 ),
      array('x' => 456, 'y' => 2675),
      array('x' => 24, 'y' => 819 ));

      foreach ($dataPoints as $key=>$value) {
        $x[$key] = $value['x'];
        $y[$key] = $value['y'];
      }
rsort($x,SORT_DESC);
rsort($y,SORT_DESC);

echo $x[0];
echo $y[0];

Answer 6

您可以通过合并array_column，min和max函数单独找到每列的最小值和最大值：

$min_x = min(array_column($dataPoints, 'x'));
$max_x = max(array_column($dataPoints, 'x'));
$min_y = min(array_column($dataPoints, 'y'));
$max_y = max(array_column($dataPoints, 'y'));

Answer 7

构建所需答案的示例代码

foreach($dataPoints[0]['x'] as $x_val)
{
//write max min func for x values
}

foreach($dataPoints[0]['y'] as $y_val)
{
//write max min func for y values
}

多维数组中的最小值和最大值

7 个答案: