Tree

class Tree(*args, **kwargs)

The GTree struct is an opaque data structure representing a [balanced binary tree][glib-Balanced-Binary-Trees]. It should be accessed only by using the following functions.

Constructors

class Tree

classmethod new_full(key_compare_func: Callable[[...], int], key_destroy_func: Callable[[None], None], *key_compare_data: Any) → Tree

Creates a new Tree like new() and allows to specify functions to free the memory allocated for the key and value that get called when removing the entry from the Tree.

Parameters:

key_compare_func – qsort()-style comparison function
key_destroy_func – a function to free the memory allocated for the key used when removing the entry from the Tree or None if you don’t want to supply such a function
key_compare_data – data to pass to comparison function

Methods

class Tree

destroy() → None: Removes all keys and values from the Tree and decreases its reference count by one. If keys and/or values are dynamically allocated, you should either free them first or create the Tree using new_full(). In the latter case the destroy functions you supplied will be called on all keys and values before destroying the Tree.

foreach(func: Callable[[...], bool], *user_data: Any) → None

Calls the given function for each of the key/value pairs in the Tree. The function is passed the key and value of each pair, and the given data parameter. The tree is traversed in sorted order.

The tree may not be modified while iterating over it (you can’t add/remove items). To remove all items matching a predicate, you need to add each item to a list in your TraverseFunc as you walk over the tree, then walk the list and remove each item.

Parameters:

func – the function to call for each node visited. If this function returns True, the traversal is stopped.
user_data – user data to pass to the function

foreach_node(func: Callable[[...], bool], *user_data: Any) → None

Calls the given function for each of the nodes in the Tree. The function is passed the pointer to the particular node, and the given data parameter. The tree traversal happens in-order.

Added in version 2.68.

Parameters:

func – the function to call for each node visited. If this function returns True, the traversal is stopped.
user_data – user data to pass to the function

height() → int

Gets the height of a Tree.

If the Tree contains no nodes, the height is 0. If the Tree contains only one root node the height is 1. If the root node has children the height is 2, etc.

insert(key: None, value: None) → None

Inserts a key/value pair into a Tree.

Inserts a new key and value into a Tree as insert_node() does, only this function does not return the inserted or set node.

Parameters:

key – the key to insert
value – the value corresponding to the key

insert_node(key: None, value: None) → TreeNode | None

Inserts a key/value pair into a Tree.

If the given key already exists in the Tree its corresponding value is set to the new value. If you supplied a value_destroy_func when creating the Tree, the old value is freed using that function. If you supplied a key_destroy_func when creating the Tree, the passed key is freed using that function.

The tree is automatically ‘balanced’ as new key/value pairs are added, so that the distance from the root to every leaf is as small as possible. The cost of maintaining a balanced tree while inserting new key/value result in a O(n log(n)) operation where most of the other operations are O(log(n)).

Added in version 2.68.

Parameters:

key – the key to insert
value – the value corresponding to the key

lookup(key: None) → None

Gets the value corresponding to the given key. Since a Tree is automatically balanced as key/value pairs are added, key lookup is O(log n) (where n is the number of key/value pairs in the tree).

Parameters:: key – the key to look up

lookup_extended(lookup_key: None) → tuple[bool, None, None]

Looks up a key in the Tree, returning the original key and the associated value. This is useful if you need to free the memory allocated for the original key, for example before calling remove().

Parameters:: lookup_key – the key to look up

lookup_node(key: None) → TreeNode | None

Gets the tree node corresponding to the given key. Since a Tree is automatically balanced as key/value pairs are added, key lookup is O(log n) (where n is the number of key/value pairs in the tree).

Added in version 2.68.

Parameters:: key – the key to look up

lower_bound(key: None) → TreeNode | None

Gets the lower bound node corresponding to the given key, or None if the tree is empty or all the nodes in the tree have keys that are strictly lower than the searched key.

The lower bound is the first node that has its key greater than or equal to the searched key.

Added in version 2.68.

Parameters:: key – the key to calculate the lower bound for

nnodes() → int: Gets the number of nodes in a Tree.

node_first() → TreeNode | None: Returns the first in-order node of the tree, or None for an empty tree.

Added in version 2.68.

node_last() → TreeNode | None: Returns the last in-order node of the tree, or None for an empty tree.

Added in version 2.68.

remove(key: None) → bool

Removes a key/value pair from a Tree.

If the Tree was created using new_full(), the key and value are freed using the supplied destroy functions, otherwise you have to make sure that any dynamically allocated values are freed yourself. If the key does not exist in the Tree, the function does nothing.

The cost of maintaining a balanced tree while removing a key/value result in a O(n log(n)) operation where most of the other operations are O(log(n)).

Parameters:: key – the key to remove
Returns:: 0 if the file was successfully removed, -1 if an error occurred

remove_all() → None: Removes all nodes from a Tree and destroys their keys and values, then resets the Tree’s root to None.

Added in version 2.70.

replace(key: None, value: None) → None

Inserts a new key and value into a Tree as replace_node() does, only this function does not return the inserted or set node.

Parameters:

key – the key to insert
value – the value corresponding to the key

replace_node(key: None, value: None) → TreeNode | None

Inserts a new key and value into a Tree similar to insert_node(). The difference is that if the key already exists in the Tree, it gets replaced by the new key. If you supplied a value_destroy_func when creating the Tree, the old value is freed using that function. If you supplied a key_destroy_func when creating the Tree, the old key is freed using that function.

The tree is automatically ‘balanced’ as new key/value pairs are added, so that the distance from the root to every leaf is as small as possible.

Added in version 2.68.

Parameters:

key – the key to insert
value – the value corresponding to the key

search(search_func: Callable[[...], int], *user_data: Any) → None

Searches a Tree using search_func.

The search_func is called with a pointer to the key of a key/value pair in the tree, and the passed in user_data. If search_func returns 0 for a key/value pair, then the corresponding value is returned as the result of search(). If search_func returns -1, searching will proceed among the key/value pairs that have a smaller key; if search_func returns 1, searching will proceed among the key/value pairs that have a larger key.

Parameters:

search_func – a function used to search the Tree
user_data – the data passed as the second argument to search_func

search_node(search_func: Callable[[...], int], *user_data: Any) → TreeNode | None

Searches a Tree using search_func.

The search_func is called with a pointer to the key of a key/value pair in the tree, and the passed in user_data. If search_func returns 0 for a key/value pair, then the corresponding node is returned as the result of search(). If search_func returns -1, searching will proceed among the key/value pairs that have a smaller key; if search_func returns 1, searching will proceed among the key/value pairs that have a larger key.

Added in version 2.68.

Parameters:

search_func – a function used to search the Tree
user_data – the data passed as the second argument to search_func

traverse(traverse_func: Callable[[...], bool], traverse_type: TraverseType, *user_data: Any) → None

Calls the given function for each node in the Tree.

Deprecated since version 2.2: The order of a balanced tree is somewhat arbitrary. If you just want to visit all nodes in sorted order, use foreach() instead. If you really need to visit nodes in a different order, consider using an [n-ary tree][glib-N-ary-Trees].

Parameters:

traverse_func – the function to call for each node visited. If this function returns True, the traversal is stopped.
traverse_type – the order in which nodes are visited, one of IN_ORDER, PRE_ORDER and POST_ORDER
user_data – user data to pass to the function

upper_bound(key: None) → TreeNode | None

Gets the upper bound node corresponding to the given key, or None if the tree is empty or all the nodes in the tree have keys that are lower than or equal to the searched key.

The upper bound is the first node that has its key strictly greater than the searched key.

Added in version 2.68.

Parameters:: key – the key to calculate the upper bound for