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"""Functions for working with hypernym/hyponym taxonomies."""
from __future__ import annotations
import wn
from wn._util import flatten
from wn.constants import ADJ, ADJ_SAT
_FAKE_ROOT = "*ROOT*"
def roots(wordnet: wn.Wordnet, pos: str | None = None) -> list[wn.Synset]:
"""Return the list of root synsets in *wordnet*.
Arguments:
wordnet: The wordnet from which root synsets are found.
pos: If given, only return synsets with the specified part of
speech.
Example:
>>> import wn, wn.taxonomy
>>> ewn = wn.Wordnet("ewn:2020")
>>> len(wn.taxonomy.roots(ewn, pos="v"))
573
"""
return [ss for ss in _synsets_for_pos(wordnet, pos) if not ss.hypernyms()]
def leaves(wordnet: wn.Wordnet, pos: str | None = None) -> list[wn.Synset]:
"""Return the list of leaf synsets in *wordnet*.
Arguments:
wordnet: The wordnet from which leaf synsets are found.
pos: If given, only return synsets with the specified part of
speech.
Example:
>>> import wn, wn.taxonomy
>>> ewn = wn.Wordnet("ewn:2020")
>>> len(wn.taxonomy.leaves(ewn, pos="v"))
10525
"""
return [ss for ss in _synsets_for_pos(wordnet, pos) if not ss.hyponyms()]
def taxonomy_depth(wordnet: wn.Wordnet, pos: str) -> int:
"""Return the maximum depth of the taxonomy for the given part of speech.
Arguments:
wordnet: The wordnet for which the taxonomy depth will be
calculated.
pos: The part of speech for which the taxonomy depth will be
calculated.
Example:
>>> import wn, wn.taxonomy
>>> ewn = wn.Wordnet("ewn:2020")
>>> wn.taxonomy.taxonomy_depth(ewn, "n")
19
"""
seen: set[wn.Synset] = set()
depth = 0
for ss in _synsets_for_pos(wordnet, pos):
if all(hyp in seen for hyp in ss.hypernyms()):
continue
paths = ss.hypernym_paths()
if paths:
depth = max(depth, max(len(path) for path in paths))
seen.update(hyp for path in paths for hyp in path)
return depth
def _synsets_for_pos(wordnet: wn.Wordnet, pos: str | None) -> list[wn.Synset]:
"""Get the list of synsets for a part of speech. If *pos* is 'a' or
's', also include those for the other.
"""
synsets = wordnet.synsets(pos=pos)
if pos == ADJ:
synsets.extend(wordnet.synsets(pos=ADJ_SAT))
elif pos == ADJ_SAT:
synsets.extend(wordnet.synsets(pos=ADJ))
return synsets
def _hypernym_paths(
synset: wn.Synset,
simulate_root: bool,
include_self: bool,
) -> list[list[wn.Synset]]:
paths = list(synset.relation_paths("hypernym", "instance_hypernym"))
if include_self:
paths = [[synset, *path] for path in paths] or [[synset]]
if simulate_root and synset.id != _FAKE_ROOT:
root = wn.Synset.empty(
id=_FAKE_ROOT, _lexicon=synset._lexicon, _lexconf=synset._lexconf
)
paths = [[*path, root] for path in paths] or [[root]]
return paths
def hypernym_paths(
synset: wn.Synset,
simulate_root: bool = False,
) -> list[list[wn.Synset]]:
"""Return the list of hypernym paths to a root synset.
Arguments:
synset: The starting synset for paths to a root.
simulate_root: If :python:`True`, find the path to a simulated
root node.
Example:
>>> import wn, wn.taxonomy
>>> dog = wn.synsets("dog", pos="n")[0]
>>> for path in wn.taxonomy.hypernym_paths(dog):
... for i, ss in enumerate(path):
... print(" " * i, ss, ss.lemmas()[0])
Synset('pwn-02083346-n') canine
Synset('pwn-02075296-n') carnivore
Synset('pwn-01886756-n') eutherian mammal
Synset('pwn-01861778-n') mammalian
Synset('pwn-01471682-n') craniate
Synset('pwn-01466257-n') chordate
Synset('pwn-00015388-n') animal
Synset('pwn-00004475-n') organism
Synset('pwn-00004258-n') animate thing
Synset('pwn-00003553-n') unit
Synset('pwn-00002684-n') object
Synset('pwn-00001930-n') physical entity
Synset('pwn-00001740-n') entity
Synset('pwn-01317541-n') domesticated animal
Synset('pwn-00015388-n') animal
Synset('pwn-00004475-n') organism
Synset('pwn-00004258-n') animate thing
Synset('pwn-00003553-n') unit
Synset('pwn-00002684-n') object
Synset('pwn-00001930-n') physical entity
Synset('pwn-00001740-n') entity
"""
return _hypernym_paths(synset, simulate_root, False)
def min_depth(synset: wn.Synset, simulate_root: bool = False) -> int:
"""Return the minimum taxonomy depth of the synset.
Arguments:
synset: The starting synset for paths to a root.
simulate_root: If :python:`True`, find the depth to a
simulated root node.
Example:
>>> import wn, wn.taxonomy
>>> dog = wn.synsets("dog", pos="n")[0]
>>> wn.taxonomy.min_depth(dog)
8
"""
return min(
(len(path) for path in synset.hypernym_paths(simulate_root=simulate_root)),
default=0,
)
def max_depth(synset: wn.Synset, simulate_root: bool = False) -> int:
"""Return the maximum taxonomy depth of the synset.
Arguments:
synset: The starting synset for paths to a root.
simulate_root: If :python:`True`, find the depth to a
simulated root node.
Example:
>>> import wn, wn.taxonomy
>>> dog = wn.synsets("dog", pos="n")[0]
>>> wn.taxonomy.max_depth(dog)
13
"""
return max(
(len(path) for path in synset.hypernym_paths(simulate_root=simulate_root)),
default=0,
)
def _shortest_hyp_paths(
synset: wn.Synset,
other: wn.Synset,
simulate_root: bool,
) -> dict[tuple[wn.Synset, int], list[wn.Synset]]:
if synset == other:
return {(synset, 0): []}
from_self = _hypernym_paths(synset, simulate_root, True)
from_other = _hypernym_paths(other, simulate_root, True)
common = set(flatten(from_self)).intersection(flatten(from_other))
if not common:
return {}
# Compute depths of common hypernyms from their distances.
# Doing this now avoid more expensive lookups later.
depths: dict[wn.Synset, int] = {}
# subpaths accumulates paths to common hypernyms from both sides
subpaths: dict[wn.Synset, tuple[list[list[wn.Synset]], list[list[wn.Synset]]]]
subpaths = {ss: ([], []) for ss in common}
for which, paths in (0, from_self), (1, from_other):
for path in paths:
for dist, ss in enumerate(path):
if ss in common:
# synset or other subpath to ss (not including ss)
subpaths[ss][which].append(path[: dist + 1])
# keep maximum depth
depth = len(path) - dist - 1
if ss not in depths or depths[ss] < depth:
depths[ss] = depth
shortest: dict[tuple[wn.Synset, int], list[wn.Synset]] = {}
for ss in common:
from_self_subpaths, from_other_subpaths = subpaths[ss]
shortest_from_self = min(from_self_subpaths, key=len)
# for the other path, we need to reverse it and remove the pivot synset
# (ty doesn't infer the result of min() correctly, hence the ignore)
shortest_from_other = min(from_other_subpaths, key=len)[-2::-1] # type: ignore
shortest[(ss, depths[ss])] = shortest_from_self + shortest_from_other
return shortest
def shortest_path(
synset: wn.Synset,
other: wn.Synset,
simulate_root: bool = False,
) -> list[wn.Synset]:
"""Return the shortest path from *synset* to the *other* synset.
Arguments:
other: endpoint synset of the path
simulate_root: if :python:`True`, ensure any two synsets
are always connected by positing a fake root node
Example:
>>> import wn, wn.taxonomy
>>> dog = ewn.synsets("dog", pos="n")[0]
>>> squirrel = ewn.synsets("squirrel", pos="n")[0]
>>> for ss in wn.taxonomy.shortest_path(dog, squirrel):
... print(ss.lemmas())
['canine', 'canid']
['carnivore']
['eutherian mammal', 'placental', 'placental mammal', 'eutherian']
['rodent', 'gnawer']
['squirrel']
"""
pathmap = _shortest_hyp_paths(synset, other, simulate_root)
key = min(pathmap, key=lambda key: len(pathmap[key]), default=None)
if key is None:
raise wn.Error(f"no path between {synset!r} and {other!r}")
return pathmap[key][1:]
def common_hypernyms(
synset: wn.Synset,
other: wn.Synset,
simulate_root: bool = False,
) -> list[wn.Synset]:
"""Return the common hypernyms for the current and *other* synsets.
Arguments:
other: synset that is a hyponym of any shared hypernyms
simulate_root: if :python:`True`, ensure any two synsets
always share a hypernym by positing a fake root node
Example:
>>> import wn, wn.taxonomy
>>> dog = ewn.synsets("dog", pos="n")[0]
>>> squirrel = ewn.synsets("squirrel", pos="n")[0]
>>> for ss in wn.taxonomy.common_hypernyms(dog, squirrel):
... print(ss.lemmas())
['entity']
['physical entity']
['object', 'physical object']
['unit', 'whole']
['animate thing', 'living thing']
['organism', 'being']
['fauna', 'beast', 'animate being', 'brute', 'creature', 'animal']
['chordate']
['craniate', 'vertebrate']
['mammalian', 'mammal']
['eutherian mammal', 'placental', 'placental mammal', 'eutherian']
"""
from_self = _hypernym_paths(synset, simulate_root, True)
from_other = _hypernym_paths(other, simulate_root, True)
common = set(flatten(from_self)).intersection(flatten(from_other))
return sorted(common, key=lambda ss: ss.id)
def lowest_common_hypernyms(
synset: wn.Synset,
other: wn.Synset,
simulate_root: bool = False,
) -> list[wn.Synset]:
"""Return the common hypernyms furthest from the root.
Arguments:
other: synset that is a hyponym of any shared hypernyms
simulate_root: if :python:`True`, ensure any two synsets
always share a hypernym by positing a fake root node
Example:
>>> import wn, wn.taxonomy
>>> dog = ewn.synsets("dog", pos="n")[0]
>>> squirrel = ewn.synsets("squirrel", pos="n")[0]
>>> len(wn.taxonomy.lowest_common_hypernyms(dog, squirrel))
1
>>> wn.taxonomy.lowest_common_hypernyms(dog, squirrel)[0].lemmas()
['eutherian mammal', 'placental', 'placental mammal', 'eutherian']
"""
pathmap = _shortest_hyp_paths(synset, other, simulate_root)
# keys of pathmap are (synset, depth_of_synset)
max_depth: int = max([depth for _, depth in pathmap], default=-1)
if max_depth == -1:
return []
else:
return [ss for ss, d in pathmap if d == max_depth]
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