collection

Generic go structures

Install

go get github.com/isgj/collection

Usage

collection.Vec[T] implemented as a native go slice []T. Because of this, other than the few currently implemented methods you can use Vec also as a regular slice.

package main

import (
	"fmt"

	"github.com/isgj/collection"
)

func main() {
	strings := collection.Vec[string]{"str1", "str2"}

	for i := 3; i < 6; i++ {
		strings = append(strings, fmt.Sprintf("str%d", i))
	}

	sliced := strings[2:4]
	indexed := strings[0]
	fmt.Printf("len=%d, cap=%d, indexed=%s, sliced=%v\n", len(strings), cap(strings), indexed, sliced)
}
// Output:
// len=5, cap=8, indexed=str1, sliced=[str3 str4]

The most noticable method of Vec is Iter (or ReverseIter) which returns a lazy iterator over the elements of the slice. Check below.

---

collection.Iterator[T] is a lazy iterator over a list of values of type T.

package main

import (
	"fmt"

	"github.com/isgj/collection"
)

func main() {
	first_slice := collection.Vec[int]{1, 2, 3, 4, 5}
	second_slice := collection.Vec[int]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14}

	result := first_slice.
		Iter().
		FollowedBy(second_slice.ReverseIter()).
		Filter(func(item int) bool {
			fmt.Printf("will test item: %2d\n", item)
			return item%2 == 0
		}).
		Skip(2).
		Take(3).
		Collect()

	fmt.Printf("len=%d, cap=%d, vec=%v\n", result.Len(), result.Cap(), result)
}
// Output:
// will test item:  1
// will test item:  2
// will test item:  3
// will test item:  4
// will test item:  5
// will test item: 14
// will test item: 12
// will test item: 10
// len=3, cap=4, vec=[14 12 10]

To note: because the iterator is lazy the test of Filter is not called on each element, but only as much as needed (no wasted calls). At the end you need to call Collect to get back a slice. If Collect is not called nothing gets executed.

---

collection.Map

collection.Set

collection.DLList

collection.LRUCache