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- test iterator end on reverse-iterable data structures

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- fix red-black tree iteration with explicit begin and end states
- examples for iterators (with index and key) (with forward and reverse iteration)
pull/20/head
Emir Pasic 8 years ago
parent 02f40db0cf
commit e49a74aa91
3 changed files with 163 additions and 24 deletions
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66
README.md
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@ -649,8 +649,9 @@ All ordered containers have stateful iterators. Typically an iterator is obtaine
#### IteratorWithIndex
A [iterator](#iterator) whose elements are referenced by an index. Typical usage:
An [iterator](#iterator) whose elements are referenced by an index.
Typical usage:
```go
it := list.Iterator()
for it.Next() {
@ -659,44 +660,89 @@ for it.Next() {
}
```
Other usages:
```go
if it.First() {
firstIndex, firstValue := it.Index(), it.Value()
...
}
```
```go
for it.Begin(); it.Next(); {
...
}
```
#### IteratorWithKey
A [iterator](#iterator) whose elements are referenced by a key. Typical usage:
An [iterator](#iterator) whose elements are referenced by a key.
Typical usage:
```go
it := map.Iterator()
it := tree.Iterator()
for it.Next() {
key, value := it.Key(), it.Value()
...
}
```
Other usages:
```go
if it.First() {
firstKey, firstValue := it.Key(), it.Value()
...
}
```
```go
for it.Begin(); it.Next(); {
...
}
```
#### ReverseIteratorWithIndex
A [iterator](#iterator) whose elements are referenced by an index. Typical usage:
An [iterator](#iterator) whose elements are referenced by an index. Provides all functions as [IteratorWithIndex](#iteratorwithindex), but can also be used for reverse iteration.
Typical usage of iteration in reverse:
```go
it := list.Iterator()
for it.Next() { /* Move to end */ }
for it.Prev() {
for it.End(); it.Prev(); {
index, value := it.Index(), it.Value()
...
}
```
Other usages:
```go
if it.Last() {
lastIndex, lastValue := it.Index(), it.Value()
...
}
```
#### ReverseIteratorWithKey
A [iterator](#iterator) whose elements are referenced by a key. Typical usage:
An [iterator](#iterator) whose elements are referenced by a key. Provides all functions as [IteratorWithKey](#iteratorwithkey), but can also be used for reverse iteration.
Typical usage of iteration in reverse:
```go
it := map.Iterator()
for it.Next() { /* Move to end */ }
for it.Prev() {
it := tree.Iterator()
for it.End(); it.Prev(); {
key, value := it.Key(), it.Value()
...
}
```
Other usages:
```go
if it.Last() {
lastKey, lastValue := it.Key(), it.Value()
...
}
```
### Enumerable
Enumerable functions for ordered containers that implement [EnumerableWithIndex](#enumerablewithindex) or [EnumerableWithKey](#enumerablewithkey) interfaces.

46
examples/main/iteratorwithindex.go → examples/iteratorwithindex.go
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@ -24,7 +24,7 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package main
package examples
import (
"fmt"
@ -32,24 +32,42 @@ import (
)
// IteratorWithIndexExample to demonstrate basic usage of IteratorWithIndex
//func IteratorWithIndexExample() {
func main() {
set := treeset.NewWithIntComparator()
set.Add(1, 2, 3)
// Forward iteration
func IteratorWithIndexExample() {
set := treeset.NewWithStringComparator()
set.Add("a", "b", "c")
it := set.Iterator()
fmt.Print("\nForward iteration\n")
for it.Next() {
index, value := it.Index(), it.Value()
fmt.Println("Index: ", index, "Value: ", value)
fmt.Print("[", index, ":", value, "]") // [0:a][1:b][2:c]
}
fmt.Print("\nForward iteration (again)\n")
for it.Begin(); it.Next(); {
index, value := it.Index(), it.Value()
fmt.Print("[", index, ":", value, "]") // [0:a][1:b][2:c]
}
fmt.Print("\nBackward iteration\n")
for it.Prev() {
index, value := it.Index(), it.Value()
fmt.Print("[", index, ":", value, "]") // [2:c][1:b][0:a]
}
// Backward iteration (reverse)
for it.Last(); ; {
fmt.Print("\nBackward iteration (again)\n")
for it.End(); it.Prev(); {
index, value := it.Index(), it.Value()
fmt.Println("Index: ", index, "Value: ", value)
if !it.Prev() {
break
}
fmt.Print("[", index, ":", value, "]") // [2:c][1:b][0:a]
}
if it.First() {
fmt.Print("\nFirst index: ", it.Index()) // First index: 0
fmt.Print("\nFirst value: ", it.Value()) // First value: a
}
if it.Last() {
fmt.Print("\nLast index: ", it.Index()) // Last index: 3
fmt.Print("\nLast value: ", it.Value()) // Last value: c
}
}

75
examples/iteratorwithkey.go
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@ -0,0 +1,75 @@
/*
Copyright (c) 2015, Emir Pasic
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package examples
import (
"fmt"
"github.com/emirpasic/gods/maps/treemap"
)
// IteratorWithKeyExample to demonstrate basic usage of IteratorWithKey
func IteratorWithKeyExample() {
m := treemap.NewWithIntComparator()
m.Put(1, "a")
m.Put(2, "b")
m.Put(3, "a")
it := m.Iterator()
fmt.Print("\nForward iteration\n")
for it.Next() {
key, value := it.Key(), it.Value()
fmt.Print("[", key, ":", value, "]") // [0:a][1:b][2:c]
}
fmt.Print("\nForward iteration (again)\n")
for it.Begin(); it.Next(); {
key, value := it.Key(), it.Value()
fmt.Print("[", key, ":", value, "]") // [0:a][1:b][2:c]
}
fmt.Print("\nBackward iteration\n")
for it.Prev() {
key, value := it.Key(), it.Value()
fmt.Print("[", key, ":", value, "]") // [2:c][1:b][0:a]
}
fmt.Print("\nBackward iteration (again)\n")
for it.End(); it.Prev(); {
key, value := it.Key(), it.Value()
fmt.Print("[", key, ":", value, "]") // [2:c][1:b][0:a]
}
if it.First() {
fmt.Print("\nFirst key: ", it.Key()) // First key: 0
fmt.Print("\nFirst value: ", it.Value()) // First value: a
}
if it.Last() {
fmt.Print("\nLast key: ", it.Key()) // Last key: 3
fmt.Print("\nLast value: ", it.Value()) // Last value: c
}
}
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