Take 返回只产出前 n 个值的读取器
(r *Reader[T], n int)
| 621 | |
| 622 | // Take 返回只产出前 n 个值的读取器 |
| 623 | func Take[T any](r *Reader[T], n int) *Reader[T] { |
| 624 | out, writer := Pipe[T](n) |
| 625 | count := 0 |
| 626 | |
| 627 | go func() { |
| 628 | defer writer.Close() |
| 629 | for count < n { |
| 630 | v, err := r.Recv() |
| 631 | if errors.Is(err, io.EOF) { |
| 632 | return |
| 633 | } |
| 634 | if err != nil { |
| 635 | writer.Send(*new(T), err) |
| 636 | return |
| 637 | } |
| 638 | if writer.Send(v, nil) { |
| 639 | return |
| 640 | } |
| 641 | count++ |
| 642 | } |
| 643 | }() |
| 644 | |
| 645 | return out |
| 646 | } |
| 647 | |
| 648 | // ForEach 消费读取器中的所有值，对每个值调用 fn |
| 649 | func ForEach[T any](r *Reader[T], fn func(T) error) error { |