概率计算函数

 

//概率计算函数
	public function get_rand($proArr) { 
		$result = ''; 	
		//概率数组的总概率精度 
		$proSum = array_sum($proArr); 	
		//概率数组循环 
		foreach ($proArr as $key => $proCur) { 
			$randNum = mt_rand(1, $proSum); 
			if ($randNum <= $proCur) { 
				$result = $key; 
				break; 
			} else { 
				$proSum -= $proCur; 
			} 
		} 
		unset ($proArr); 	
		return $result; 
	}