https://github.com/chippyash/go-hierarchy-tree
Basic but useful hierarchical tree, a form of directed graph
https://github.com/chippyash/go-hierarchy-tree
Last synced: about 1 month ago
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Basic but useful hierarchical tree, a form of directed graph
- Host: GitHub
- URL: https://github.com/chippyash/go-hierarchy-tree
- Owner: chippyash
- License: bsd-3-clause
- Created: 2022-08-06T10:51:48.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2022-08-06T12:40:34.000Z (almost 4 years ago)
- Last Synced: 2025-01-14T03:34:14.863Z (over 1 year ago)
- Language: Go
- Size: 15.6 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# Hierarchy tree for Go
## github.com/chippyash/go-hierarchy-tree/tree
Go: 1.18
## What
Provides a basic but flexible hierarchical tree data structure together with an implementation of a
Visitor pattern for tree manipulation.
## How
`import "github.com/chippyash/go-hierarchy-tree/tree"`
### For Development
#### Setup
- clone repository
- cd to project directory
- `go get ./...`
#### Usage
##### Create a node
```go
import "github.com/chippyash/go-hierarchy-tree/tree"
//node with no value or children
node := tree.NewNode(nil, nil)
//node with some value
node := tree.NewNode("foo", nil)
//node with children
child1 := tree.NewNode("bar", nil)
child2 := tree.NewNode("baz", nil)
children := []tree.NodeIFace{child1, child2}
node := tree.NewNode("foo", &children)
```
##### Getting and setting a node value
A node can have any value. The value of a node is an interface{}
```go
val := tree.NewNode(nil, nil).
SetValue("foo").
GetValue()
```
##### Adding one or more children
You can add children when you construct a node (see above) or afterwards.
```go
child1 := tree.NewNode(1, nil)
child2 := tree.NewNode(2, nil)
children := []tree.NodeIFace{child1, child2}
childNodes := tree.NewNode(0, nil).
SetChildren(children...).
GetChildren()
childNodes = tree.NewNode(0, nil).
AddChild(child1).
AddChild(child2).
GetChildren()
```
##### Removing child nodes
```go
node.RemoveChild(child1)
node.RemoveAllChildren()
```
##### Testing nodes
```go
node.IsLeaf() //true if node has no children
node.IsRoot() //true if node is the root node, i.e. no parent
node.IsChild() //true if node has a parent
```
##### Parents, siblings and ancestors
```go
node.SetParent(someOtherNode) //set the parent to the node
node.GetParent() //return parent of this node - nil if node is root
node.GetSiblings() //returns nodes with same parent
node.GetSiblingsAndSelf() //returns nodes with same parent including self
node.GetAncestors() //parents and grandparents
node.GetAncestorsAndSelf() //self, parents and grandparents
```
##### Traversing a tree
The tree implements the Visitor pattern Accept method.
###### Pre-order traversal
```go
/**
* root
* /|\
* a b c
* /| |
* d e f
*/
visitor := tree.NewPreOrderVisitor()
result := root.Accept(visitor)
//returns []tree.NodeIFace{root, a, d, e, b, f, c}
```
###### Post-order traversal
```go
/**
* root
* /|\
* a b c
* /| |
* d e f
*/
visitor := tree.NewPostOrderVisitor()
result := root.Accept(visitor)
//returns []tree.NodeIFace{d, e, a, f, b, c, root}
```
###### Gathering leaves
```go
/**
* root
* /|\
* a b c
* /| |
* d e f
*/
visitor := tree.NewLeafVisitor()
result := root.Accept(visitor)
//returns []tree.NodeIFace{d, e, f, c}
```
##### Filtering
```go
/**
* root
* /|\
* a b c
* /| |
* d e f
*/
visitor := tree.NewFilterVisitor(func(n tree.NodeIFace) bool {
return n.GetValue() == "e"
})
result := root.Accept(visitor)
//returns []tree.NodeIFace{e}
```
see [Filter Test](tree/filter_test.go) for other examples
##### Node information
```go
node.GetDepth() //returns the distance from the current node to the root
node.GetHeight() //returns the height of the tree whose root is this node
node.GetSize() //returns the number of nodes in the tree rooted at this node
```
#### Testing
`go test ./...`
#### Before you do a PR
- Update the readme if necessary
## References
- [Github](https://github.com/chippyash/go-hierarchy-tree)
- [Based on Nicmart/Tree](https://github.com/nicmart/Tree)