計算數組平均值 二維數組平均值計算 分組計算平均值
| 代碼如下 |
複製代碼 |
$array = array(
array('class' => 'a', 'value' => 3),
array('class' => 'a', 'value' => 4),
array('class' => 'b', 'value' => 5),
array('class' => 'b', 'value' => 6)
) |
這樣的數組可分別以 class索引值分組計算平均值
也可以單獨計算總的平均值，用法如下
| 代碼如下 |
複製代碼 |
array_avg($array, 'class');//返回二維數組
array_avg($array);//返回一維數組
// 計算平均值 返回一維數組
// 參數$avgby 按照指定欄位算平均值 返回二維數組
private function array_avg($array, $avgby = NULL) {
$array_avg = array ();
$number = count ( $array );
foreach ( $array as $key => $value ) {
if ($avgby) {
$avg_key = $value[$avgby];
$array_avg[$avg_key]['count'] ++;
foreach ( $value as $k => $v ) {
$array_avg[$avg_key][$k] += $v;
}
} else {
foreach ( $value as $k => $v ) {
$array_avg[$k] += $v;
}
}
}
$array = array ();
foreach ( $array_avg as $key => $value ) {
if ($avgby) {
foreach ( $value as $k => $v ) {
$array[$key][$k] = $v / $value['count'];
}
} else {
$array[$key] = $value / $number;
}
}
return $array;
} |
