php实现按照权重随机排序数据的方法

<?php
/**
* @param array $weight 权重 例如array('a'=>10,'b'=>20,'c'=>50)
* @return string key 键名
*/
function roll($weight = array()) {
$roll = rand ( 1, array_sum ( $weight ) );
$_tmpW = 0;
$rollnum = 0;
foreach ( $weight as $k => $v ) {
$min = $_tmpW;
$_tmpW += $v;
$max = $_tmpW;
if ($roll > $min && $roll <= $max) {
$rollnum = $k;
break;
}
}
return $rollnum;
}

$row=roll(array('a'=>10,'b'=>20,'c'=>50));
echo $row;
?>

希望本文所述对大家的php程序设计有所帮助。