我可以这样做
IWeightedRandomizer<string> randomizer = new DynamicWeightedRandomizer<string>();
randomizer["Joe"] = 1;
randomizer["Ryan"] = 2;
randomizer["Jason"] = 2;
string name1 = randomizer.RandomWithReplacement();
//name1 has a 20% chance of being "Joe", 40% of "Ryan", 40% of "Jason"
string name2 = randomizer.RandomWithRemoval();
//Same as above, except whichever one was chosen has been removed from the list.
但这不起作用。
strptime("20150615",format="%Y%m%d")
这是怎么回事？
修改
现在这样做却太傻了。
strptime("194207","%Y%m")
[1] NA