小编Свя*_*лав的帖子

情况1

1. 从序列中获取价值
2. 打印一些值

let a = seq { yield Some 1; yield Some 2; yield Some 3; yield None }

a
|> Seq.takeWhile Option.isSome // cast 1
|> Seq.map Option.get          // cast 2
|> Seq.iter (printfn "%A")

情况二

1. 一些值的过滤序列
2. 打印某些值

a
|> Seq.filter Option.isSome    // cast 1
|> Seq.map Option.get          // cast 2
|> Seq.iter (printfn "%A")

情况3

1. 按类型按元素分组
2. 打印每组的值

type AB =
    | A of a : int
    | B of b : string

let a = seq{
    yield …