PHP游戏概率方法

<?php function createRandomKey($randArr, $rateKey){ ???????$total = 0; ???????$chooseArr = array(); ???????$pow = 0; ???????foreach($randArr as $k => $v){ ???????????$tmp = explode(‘.‘, strval($v[$rateKey])); ???????????if($tmp[1] && strlen($tmp[1]) > $pow){ ???????????????$pow = strlen($tmp[1]); ???????????} ???????} ???????$r = pow(10, $pow); ???????foreach($randArr as $key => $value){ ???????????$total = $total + $value[$rateKey] * $r; ???????????$chooseArr[$key] = $total; ???????}; ???????$rand = rand(1, $total); ???????$bofore = 0; ???????foreach ($chooseArr as $k => $v){ ???????????$v = $v * $r; ???????????if($rand > $before && $rand <= $v){ ??????????????$chooseIndex = $k; ???????????????break; ???????????} ???????????$before = $v; ???????} ???????return $chooseIndex; ???} ???????$randArr = [ ???????????0 => [‘point‘ => 15,‘rate‘ => 0], ???????????1 => [‘point‘ => 5,‘rate‘ => 0], ???????????2 => [‘point‘ => 10,‘rate‘ => 0], ???????????3 => [‘point‘ => 11,‘rate‘ => 0], ???????????4 => [‘point‘ => 13,‘rate‘ => 10], ???????????5 => [‘point‘ => 20,‘rate‘ => 80], ???????????6 => [‘point‘ => 50,‘rate‘ => 0], ???????????7 => [‘point‘ => 80,‘rate‘ => 0], ???????????8 => [‘point‘ => 10,‘rate‘ => 0], ???????????9 => [‘point‘ => 60,‘rate‘ => 10], ???????????????]; ???????$a = createRandomKey($randArr,$rate = ‘rate‘); ???var_dump($a); ???var_dump($randArr[$a][‘point‘]);