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Tree and List

Tree class

When instantiating a class, you can use some settings

id_key

  Id of the node.

parent_key

  Parent node id. This id has to match the id_key that identifies a parent node.

child_key

  When you create a tree from a list, this value will be the name of the key which will be a list of child nodes. If used when creating a list from a tree, this value will be used to identify the key that contains the list with the child nodes.

parent_start

  This is the value that defines a parent node. Ex: "0", "None".

flow_key

  when a tree is created from a list, will automatically be created in the key in the dictionary called "flow" that contains the current node sequence. Ex: "flow": "1-1-2".

flow

  Receives a boolean value that generates the flow_key or not.

The default values ​​are:

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id_key: str = "id"

parent_key: str = "parent"

parent_start: Any = "0"

child_key: str = "children"

flow_key: str = "flow"

flow: bool = True

Tree from List

Default values

In this example contains 2 trees in the list.

  • The value "0" will be used to identify the parent node.
  • The value of the key that contains the id of the node is "id"
  • The value of the key that contains the id of the parent node is "parent"
  • The key value that will be created with the list of child nodes will be "children"
  • A key named "flow" will be automatically created with the current sequence of each node
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import json

from tree_parsing import Tree


list_tree = [
    {"id": 1, "parent": 0},
    {"id": 2, "parent": 1},
    {"id": 3, "parent": 1},
    {"id": 4, "parent": 2},
    {"id": 5, "parent": 0},
    {"id": 6, "parent": 5},
    {"id": 7, "parent": 5},
]

tr = Tree(id_key="id", parent_key="parent", parent_start="0", child_key="children")
tree = tr.tree_from_list(list_tree)
print(json.dumps(tree, indent=4))

Output:

[
    {
        "id": 1,
        "parent": 0,
        "flow": "1",
        "children": [
            {
                "id": 2,
                "parent": 1,
                "flow": "1-1",
                "children": [
                    {
                        "id": 4,
                        "parent": 2,
                        "flow": "1-1-1"
                    }
                ]
            },
            {
                "id": 3,
                "parent": 1,
                "flow": "1-2"
            }
        ]
    },
    {
        "id": 5,
        "parent": 0,
        "flow": "2",
        "children": [
            {
                "id": 6,
                "parent": 5,
                "flow": "2-1"
            },
            {
                "id": 7,
                "parent": 5,
                "flow": "2-2"
            }
        ]
    }
]

Flow Key

In this example the value of the key flow will be changed to sequence.

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import json

from tree_parsing import Tree


list_tree = [
    {"id": 1, "parent": 0},
    {"id": 2, "parent": 1},
    {"id": 3, "parent": 1},
    {"id": 4, "parent": 0},
]

tr = Tree(flow_key="sequence")
tree = tr.tree_from_list(list_tree)
print(json.dumps(tree, indent=4))

Output:

[
    {
        "id": 1,
        "parent": 0,
        "sequence": "1",
        "children": [
            {
                "id": 2,
                "parent": 1,
                "sequence": "1-1"
            },
            {
                "id": 3,
                "parent": 1,
                "sequence": "1-2"
            }
        ]
    },
    {
        "id": 4,
        "parent": 0,
        "sequence": "2"
    }
]

You can disable the "flow_key".

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import json

from tree_parsing import Tree


list_tree = [
    {"id": 1, "parent": 0},
    {"id": 2, "parent": 1},
    {"id": 3, "parent": 1},
    {"id": 4, "parent": 0},
]

tr = Tree(flow=False)
tree = tr.tree_from_list(list_tree)
print(json.dumps(tree, indent=4))

Output:

[
    {
        "id": 1,
        "parent": 0,
        "children": [
            {
                "id": 2,
                "parent": 1
            },
            {
                "id": 3,
                "parent": 1
            }
        ]
    },
    {
        "id": 4,
        "parent": 0
    }
]

List from Tree

Maybe you already have a tree and want to turn it into a list with all the nodes. Then you can pass a list of trees to turn into a list of nodes.

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import json

from tree_parsing import Tree

my_tree = [
    {
        "id": 1,
        "parent": 0,
        "children": [
            {
                "id": 2,
                "parent": 1
            },
            {
                "id": 3,
                "parent": 1
            }
        ]
    },
    {
        "id": 4,
        "parent": 0
    }
]

tr = Tree()
list_tree = tr.list_from_tree(my_tree)
print(json.dumps(list_tree, indent=1))

Output:

[
 {
  "id": 1,
  "parent": 0
 },
 {
  "id": 2,
  "parent": 1
 },
 {
  "id": 3,
  "parent": 1
 },
 {
  "id": 4,
  "parent": 0
 }
]