Huangzj
88 lines
2.2 KiB
Go
88 lines
2.2 KiB
Go
package linq
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// Intersect produces the set intersection of the source collection and the
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// provided input collection. The intersection of two sets A and B is defined as
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// the set that contains all the elements of A that also appear in B, but no
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// other elements.
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func (q Query) Intersect(q2 Query) 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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next2 := q2.Iterate()
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set := make(map[interface{}]bool)
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for item, ok := next2(); ok; item, ok = next2() {
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set[item] = true
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}
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return func() (item interface{}, ok bool) {
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for item, ok = next(); ok; item, ok = next() {
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if _, has := set[item]; has {
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delete(set, item)
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return
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}
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}
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return
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}
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},
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}
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}
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// IntersectBy produces the set intersection of the source collection and the
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// provided input collection. The intersection of two sets A and B is defined as
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// the set that contains all the elements of A that also appear in B, but no
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// other elements.
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//
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// IntersectBy invokes a transform function on each element of both collections.
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func (q Query) IntersectBy(q2 Query,
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selector func(interface{}) interface{}) 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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next2 := q2.Iterate()
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set := make(map[interface{}]bool)
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for item, ok := next2(); ok; item, ok = next2() {
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s := selector(item)
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set[s] = true
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}
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return func() (item interface{}, ok bool) {
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for item, ok = next(); ok; item, ok = next() {
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s := selector(item)
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if _, has := set[s]; has {
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delete(set, s)
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return
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}
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}
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return
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}
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},
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}
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}
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// IntersectByT is the typed version of IntersectBy.
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//
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// - selectorFn is of type "func(TSource) TSource"
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//
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// NOTE: IntersectBy has better performance than IntersectByT.
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func (q Query) IntersectByT(q2 Query,
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selectorFn interface{}) Query {
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selectorGenericFunc, err := newGenericFunc(
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"IntersectByT", "selectorFn", selectorFn,
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simpleParamValidator(newElemTypeSlice(new(genericType)), newElemTypeSlice(new(genericType))),
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)
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if err != nil {
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panic(err)
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}
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selectorFunc := func(item interface{}) interface{} {
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return selectorGenericFunc.Call(item)
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}
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return q.IntersectBy(q2, selectorFunc)
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}
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