我正在找人指出正确的方向来编写一些统计比较。目前我查询我的数据库，并将返回数据如下：
主要数据集：
3,4,7,10,5,8,1,3,7
要比较的集合可以是这样的，并且可以有多个集合。
4,5,6,9,10,2,3,4,6
现在我需要计算出这两组数据之间的差异——例如，3-4 之间的差异是 1。然后我需要选择最大的差异、最同意的和最低的得分。
你会如何处理这个编码？
【问题讨论】：
标签： php mysql comparison
我建议使用函数array_walk()，将第一个数组作为第一个参数，将第二个数组作为第三个可选参数。它看起来像这样：
<?php
$array_1 = array(3,4,7,10,5,8,1,3,7);
$array_2 = array(4,5,6,9,10,2,3,4,6);
// making a copy, because the callback function
// works on the actual value
$array_1_copy = $array_1;
echo '<pre>';
array_walk($array_1_copy, 'difference', $array_2);
echo "\nThe maximum difference is: ". max($array_1_copy);
echo "\nThe minimum difference is: ". min($array_1_copy);
echo '</pre>';
// the callback function, takes the 1st param as reference
function difference(&$value_1, $index_1, $array_2) {
$difference = abs($value_1 - $array_2[$index_1]);
echo "Difference between $value_1 and {$array_2[$index_1]} is $difference\n";
$value_1 = $difference;
}
?>
这段代码的输出是：
Difference between 3 and 4 is 1
Difference between 4 and 5 is 1
Difference between 7 and 6 is 1
Difference between 10 and 9 is 1
Difference between 5 and 10 is 5
Difference between 8 and 2 is 6
Difference between 1 and 3 is 2
Difference between 3 and 4 is 1
Difference between 7 and 6 is 1
The maximum difference is: 6
The minimum difference is: 1
【讨论】：
$max_diff = 0;
for ($i = 0; $i < (min(count($array1), count($array2));$i++){
if (($array1[$i]-$array2[$i]) > $max_diff ) $max_diff = $array1[$i]-$array2[$i];
}
echo $max_diff;
类似的东西......实际上并没有测试它，但就是这样。
【讨论】：