Choose by probability 根据概率进行选择
说明
Given an array (assuming a length of N), the array contains probabilities. Based on these probabilities, make a selection. The result is one of N numbers from 1 to N (given array length).
给定一个数组（假定长度为N），数组内包含的是概率。根据这些概率，进行选择。结果为1到N（给定的数组长度）这N个数之一。
Example 例子
We called choose used the array [0.1, 0.2, 0.3, 0.4, 0.5] 150000 times and obtained the result:
我们使用数组[0.1, 0.2, 0.3, 0.4, 0.5]调用150000次，得到结果：
1 => 9960
2 => 20068
3 => 29982
4 => 40124
5 => 49866
This result matches the probability array.
这个结果跟概率数组是匹配的。