GLib.HashTable

Fields

None

Methods

class

add (hash_table, key)

class

contains (hash_table, key)

class

destroy (hash_table)

class

insert (hash_table, key, value)

class

lookup (hash_table, key)

class

lookup_extended (hash_table, lookup_key)

class

new_similar (other_hash_table)

class

remove (hash_table, key)

class

remove_all (hash_table)

class

replace (hash_table, key, value)

class

size (hash_table)

class

steal (hash_table, key)

class

steal_all (hash_table)

class

steal_extended (hash_table, lookup_key)

class

unref (hash_table)

Details

class GLib.HashTable

The GLib.HashTable struct is an opaque data structure to represent a Hash Table. It should only be accessed via the following functions.

classmethod add(hash_table, key)[source]
Parameters
Returns

True if the key did not exist yet

Return type

bool

This is a convenience function for using a GLib.HashTable as a set. It is equivalent to calling GLib.HashTable.replace() with key as both the key and the value.

In particular, this means that if key already exists in the hash table, then the old copy of key in the hash table is freed and key replaces it in the table.

When a hash table only ever contains keys that have themselves as the corresponding value it is able to be stored more efficiently. See the discussion in the section description.

Starting from GLib 2.40, this function returns a boolean value to indicate whether the newly added value was already in the hash table or not.

New in version 2.32.

classmethod contains(hash_table, key)[source]
Parameters
Returns

True if key is in hash_table, False otherwise.

Return type

bool

Checks if key is in hash_table.

New in version 2.32.

classmethod destroy(hash_table)[source]
Parameters

hash_table ({object: object}) – a GLib.HashTable

Destroys all keys and values in the GLib.HashTable and decrements its reference count by 1. If keys and/or values are dynamically allocated, you should either free them first or create the GLib.HashTable with destroy notifiers using g_hash_table_new_full(). In the latter case the destroy functions you supplied will be called on all keys and values during the destruction phase.

classmethod insert(hash_table, key, value)[source]
Parameters
Returns

True if the key did not exist yet

Return type

bool

Inserts a new key and value into a GLib.HashTable.

If the key already exists in the GLib.HashTable its current value is replaced with the new value. If you supplied a value_destroy_func when creating the GLib.HashTable, the old value is freed using that function. If you supplied a key_destroy_func when creating the GLib.HashTable, the passed key is freed using that function.

Starting from GLib 2.40, this function returns a boolean value to indicate whether the newly added value was already in the hash table or not.

classmethod lookup(hash_table, key)[source]
Parameters
Returns

the associated value, or None if the key is not found

Return type

object or None

Looks up a key in a GLib.HashTable. Note that this function cannot distinguish between a key that is not present and one which is present and has the value None. If you need this distinction, use GLib.HashTable.lookup_extended().

classmethod lookup_extended(hash_table, lookup_key)[source]
Parameters
Returns

True if the key was found in the GLib.HashTable

orig_key

return location for the original key

value

return location for the value associated with the key

Return type

(bool, orig_key: object, value: object)

Looks up a key in the GLib.HashTable, returning the original key and the associated value and a bool which is True if the key was found. This is useful if you need to free the memory allocated for the original key, for example before calling GLib.HashTable.remove().

You can actually pass None for lookup_key to test whether the None key exists, provided the hash and equal functions of hash_table are None-safe.

classmethod new_similar(other_hash_table)[source]
Parameters

other_hash_table ({object: object}) – Another GLib.HashTable

Returns

a new GLib.HashTable

Return type

{object: object}

Creates a new GLib.HashTable like g_hash_table_new_full() with a reference count of 1.

It inherits the hash function, the key equal function, the key destroy function, as well as the value destroy function, from other_hash_table.

The returned hash table will be empty; it will not contain the keys or values from other_hash_table.

New in version 2.72.

classmethod remove(hash_table, key)[source]
Parameters
Returns

True if the key was found and removed from the GLib.HashTable

Return type

bool

Removes a key and its associated value from a GLib.HashTable.

If the GLib.HashTable was created using g_hash_table_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.

classmethod remove_all(hash_table)[source]
Parameters

hash_table ({object: object}) – a GLib.HashTable

Removes all keys and their associated values from a GLib.HashTable.

If the GLib.HashTable was created using g_hash_table_new_full(), the keys and values are freed using the supplied destroy functions, otherwise you have to make sure that any dynamically allocated values are freed yourself.

New in version 2.12.

classmethod replace(hash_table, key, value)[source]
Parameters
Returns

True if the key did not exist yet

Return type

bool

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

Starting from GLib 2.40, this function returns a boolean value to indicate whether the newly added value was already in the hash table or not.

classmethod size(hash_table)[source]
Parameters

hash_table ({object: object}) – a GLib.HashTable

Returns

the number of key/value pairs in the GLib.HashTable.

Return type

int

Returns the number of elements contained in the GLib.HashTable.

classmethod steal(hash_table, key)[source]
Parameters
Returns

True if the key was found and removed from the GLib.HashTable

Return type

bool

Removes a key and its associated value from a GLib.HashTable without calling the key and value destroy functions.

classmethod steal_all(hash_table)[source]
Parameters

hash_table ({object: object}) – a GLib.HashTable

Removes all keys and their associated values from a GLib.HashTable without calling the key and value destroy functions.

New in version 2.12.

classmethod steal_extended(hash_table, lookup_key)[source]
Parameters
Returns

True if the key was found in the GLib.HashTable

stolen_key

return location for the original key

stolen_value

return location for the value associated with the key

Return type

(bool, stolen_key: object, stolen_value: object)

Looks up a key in the GLib.HashTable, stealing the original key and the associated value and returning True if the key was found. If the key was not found, False is returned.

If found, the stolen key and value are removed from the hash table without calling the key and value destroy functions, and ownership is transferred to the caller of this method, as with GLib.HashTable.steal(). That is the case regardless whether stolen_key or stolen_value output parameters are requested.

You can pass None for lookup_key, provided the hash and equal functions of hash_table are None-safe.

The dictionary implementation optimizes for having all values identical to their keys, for example by using GLib.HashTable.add(). When stealing both the key and the value from such a dictionary, the value will be None.

New in version 2.58.

classmethod unref(hash_table)[source]
Parameters

hash_table ({object: object}) – a valid GLib.HashTable

Atomically decrements the reference count of hash_table by one. If the reference count drops to 0, all keys and values will be destroyed, and all memory allocated by the hash table is released. This function is MT-safe and may be called from any thread.

New in version 2.10.