在一个linq查询中使用了平均值聚合函数Average,结果报错 System.InvalidOperationException Sequence contains no elements (序列不包含任何元素) 也就是说,使用某些linq的函数时,如果值不存在是会报错的,比如: First()Single()FirstAsync()SingleAsync()Last()LastAsync()Max()Min()Average() 等, 解决方案: 使用空...
When you start playing with LINQ queries over sequences of elements (e.g. getting min / max value for enumerable source) sooner or later you will come across this one -- the InvalidOperationException (“Sequence contains no elements”). The problem occurs as by default queries like IEnumerabl...
一、在.Net Core中使用Ef的聚合函数报错: 类似函数: 1,使用FirstOrDefault() 来代替 First() 2、使用SingleOrDefault 来代替 Single 3、使用 ElementAtOrDefault 来代替 .ElementAt 4、如果是在Average, Sum等中报错 错误如下: Sequence contains no elements 二、在.Net Core的 内存列表 Linq 聚合函数解决方案 v...
一、在.Net Core中使用Ef的聚合函数报错: 类似函数: 1,使用FirstOrDefault() 来代替 First() 2、使用SingleOrDefault 来代替 Single 3、使用 ElementAtOrDefault 来代替 .ElementAt 4、如果是在Average, Sum等中报错 错误如下: Sequence contains no elements 二、在.Net Core的 内存列表 Linq 聚合函数解决方案 v...
After update to dotnet core 3.0 RC1 running following code var value = context.Products.Where(t => t.CategoryId == catId).Select(t => t.Version).DefaultIfEmpty().Max(); throws System.InvalidOperationException: Sequence contains no elemen...
The third element type, closed-chromatin enhancers, are located in regions that show little or no signal for DNase I hypersensitivity or ATAC-seq. They are not silenced by CpG methylation. These elements appear to consist of only a single TF (e.g., p53; see also Peng et al.42) or a...
L1 is the only abundant and active LINE in the human genome, and the human genome contains an estimated 100,000 truncated and 4000 full-length L1 elements accounting for about 17% of the entire genome82. Since L1 correlations with disease and immunity by producing gene mutations, it has ...
Finding Elements func contains(Self.Element) -> Bool Returns a Boolean value indicating whether the sequence contains the given element. Available when Element conforms to Equatable. func contains(where: (Self.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether the...
Seq.countBy then returns a sequence that contains the key values, and a count of the number of elements that generated each value of the key.F# 複製 let mySeq1 = seq { 1.. 100 } let printSeq seq1 = Seq.iter (printf "%A ") seq1; printfn "" let seqResult = Seq.countBy (...
The final codeword contains no 0s and is 3 bits long. Because all other codewords have fewer than three 1s and terminate in a 0, the only way we can get three 1s in a row is as a code for a4. The decoding rule is simple. Accumulate bits until you get a 0 or until you have...