我可以简化这个LINQ查询吗?
本文关键字:查询 LINQ 我可以 | 更新日期: 2023-09-27 18:05:03
我正在学习LINQ,我想知道是否有可能简化以下LINQ查询…
现在我有两个字符串,我解析连接的字符串来计算每个单词的使用次数。我想知道是否有可能保持一个LINQ表达式,但不必复制字符串。在from和let表达式中连接部分
string sentence = "this is the first sentence";
string sentence2 = "this is the second sentence";
var res = from word in string.Concat(sentence, sentence2).Split()
let combinedwords = string.Concat(sentence, sentence2).Split()
select new { TheWord = word, Occurance = combinedwords.Count(x => x.Equals(word)) };
您的查询返回了一个有点奇怪的结果集:
TheWord Occurrence
this 1
is 2
the 2
first 1
sentencethis 1
is 2
the 2
second 1
sentence 1
这是你想要的,还是你更喜欢这样的结果?
TheWord Occurrence
this 2
is 2
the 2
first 1
sentence 2
second 1
要得到这些结果,你可以这样做:
var res = from word in sentence.Split()
.Concat(sentence2.Split())
group word by word into g
select new { TheWord = g.Key, Occurrence = g.Count() };
另一种选择;更好的(理论)性能,但可读性较差:
var res = sentence.Split()
.Concat(sentence2.Split())
.Aggregate(new Dictionary<string, int>(),
(a, x) => {
int count;
a.TryGetValue(x, out count);
a[x] = count + 1;
return a;
},
a => a.Select(x => new {
TheWord = x.Key,
Occurrence = x.Value
}));