Huangzj
85 lines
1.6 KiB
Go
85 lines
1.6 KiB
Go
package linq
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// Take returns a specified number of contiguous elements from the start of a collection.
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func (q Query) Take(count int) Query {
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return Query{
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Iterate: func() Iterator {
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next := q.Iterate()
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n := count
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return func() (item interface{}, ok bool) {
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if n <= 0 {
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return
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}
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n--
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return next()
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}
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},
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}
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}
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// TakeWhile returns elements from a collection as long as a specified condition is true,
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// and then skips the remaining elements.
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func (q Query) TakeWhile(predicate func(interface{}) bool) Query {
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return Query{
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Iterate: func() Iterator {
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next := q.Iterate()
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done := false
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return func() (item interface{}, ok bool) {
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if done {
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return
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}
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item, ok = next()
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if !ok {
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done = true
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return
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}
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if predicate(item) {
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return
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}
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done = true
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return nil, false
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}
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},
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}
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}
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// TakeWhileIndexed returns elements from a collection as long as a specified condition
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// is true. The element's index is used in the logic of the predicate function.
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// The first argument of predicate represents the zero-based index of the element
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// within collection. The second argument represents the element to test.
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func (q Query) TakeWhileIndexed(predicate func(int, interface{}) bool) Query {
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return Query{
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Iterate: func() Iterator {
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next := q.Iterate()
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done := false
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index := 0
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return func() (item interface{}, ok bool) {
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if done {
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return
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}
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item, ok = next()
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if !ok {
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done = true
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return
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}
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if predicate(index, item) {
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index++
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return
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}
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done = true
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return nil, false
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}
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},
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}
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}
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