您好，我想做的很简单，我有一个List<tuple>(string, decimal)，如果有两个相似的字符串，我想获取十进制值的总和.
Hello what I'm trying to do is hopefully simple, I have a List<tuple>(string, decimal) and I'm trying to grab the sum of the decimal values if there are two similar strings.
我的列表包含以下值:
- ("q"，.5)
- ("w"，1.5)
- ("e"，.7)
- ("r"，.8)
- ("q"，.5)
因此，所有值的总和为.5 + 1.5 + .7 + .8 + .5 = 4.0.
The sum of all the values would therefore be .5 + 1.5 + .7 + .8 + .5 = 4.0.
我认为算法将是这样的:
I assume the algorithm would be something like this:
newlist.select(item1 , item2).where(get the sum of first "q" up to the next "q" in list)对于现有代码，我不仅只有列表的声明及其值.
As for existing code, I don't have much only the declaration of the list and it's values.
**我想要'q'和'q'之间的总和+'q'和'q'的值，而不仅仅是中间值，答案应该是'4'而不是3，我希望所有之间q和q包括q的值，谢谢.
**I want the sum between 'q' and 'q' + the values of 'q' and 'q', not just in-between, the answer should be '4' and not 3, I want everything between q and q including q's values, thank you.
推荐答案您可以使用简单的Linq扩展名， SkipWhile 和 TakeWhile
You could use simple Linq extensions, SkipWhile and TakeWhile
List<Tuple<string,double>> items = new List<Tuple<string,double>>() { new Tuple<string,double>("q", .5), new Tuple<string,double>("w", 1.5), new Tuple<string,double>("e", .7), new Tuple<string,double>("r", .8), new Tuple<string,double>("q", .5) }; var sumvalue = items.Sum(c=>c.Item2); // Calculates sum of all values var betweensum = items.SkipWhile(x=>x.Item1 == "q") // Skip until matching item1 .TakeWhile(x=>x.Item1 != "q") // take until matching item1 .Sum(x=>x.Item2); // Sum按照评论中的要求，如果您有多个这样的集合，并且想要在多个集合的匹配字符串之间进行计数，请执行此操作.
As asked in the comments, in case if you have multiple such sets and you want count in between those matching strings for multiple sets, do this.
int gid = 0; items.Select(c => new { Tuple = c, gid = c.Item1=="q"? ++gid : gid }) .GroupBy(x=>x.gid) .Where(x=>x.Key%2==1) .SelectMany(x=>x.Skip(1)) .Sum(x=>x.Tuple.Item2);工作 Demo