Bohye.Woo
/
bo-graduation
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
master
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from 'c4efb03a00'
${ noResults }
bo-graduation/venv/lib/python3.7/site-packages/nltk/test/tree.doctest

1102 lines
39 KiB
Plaintext
Raw Normal View History Unescape Escape

readme check
5 years ago
.. Copyright (C) 2001-2019 NLTK Project
.. For license information, see LICENSE.TXT
===============================
Unit tests for nltk.tree.Tree
===============================
>>> from nltk.tree import *
Some trees to run tests on:
>>> dp1 = Tree('dp', [Tree('d', ['the']), Tree('np', ['dog'])])
>>> dp2 = Tree('dp', [Tree('d', ['the']), Tree('np', ['cat'])])
>>> vp = Tree('vp', [Tree('v', ['chased']), dp2])
>>> tree = Tree('s', [dp1, vp])
>>> print(tree)
(s (dp (d the) (np dog)) (vp (v chased) (dp (d the) (np cat))))
The node label is accessed using the `label()` method:
>>> dp1.label(), dp2.label(), vp.label(), tree.label()
('dp', 'dp', 'vp', 's')
>>> print(tree[1,1,1,0])
cat
The `treepositions` method returns a list of the tree positions of
subtrees and leaves in a tree. By default, it gives the position of
every tree, subtree, and leaf, in prefix order:
>>> print(tree.treepositions())
[(), (0,), (0, 0), (0, 0, 0), (0, 1), (0, 1, 0), (1,), (1, 0), (1, 0, 0), (1, 1), (1, 1, 0), (1, 1, 0, 0), (1, 1, 1), (1, 1, 1, 0)]
In addition to `str` and `repr`, several methods exist to convert a
tree object to one of several standard tree encodings:
>>> print(tree.pformat_latex_qtree())
\Tree [.s
[.dp [.d the ] [.np dog ] ]
[.vp [.v chased ] [.dp [.d the ] [.np cat ] ] ] ]
There is also a fancy ASCII art representation:
>>> tree.pretty_print()
s
________|_____
| vp
| _____|___
dp | dp
___|___ | ___|___
d np v d np
| | | | |
the dog chased the cat
>>> tree.pretty_print(unicodelines=True, nodedist=4)
s
┌──────────────┴────────┐
│ vp
│ ┌────────┴──────┐
dp │ dp
┌──────┴──────┐ │ ┌──────┴──────┐
d np v d np
│ │ │ │ │
the dog chased the cat
Trees can be initialized from treebank strings:
>>> tree2 = Tree.fromstring('(S (NP I) (VP (V enjoyed) (NP my cookie)))')
>>> print(tree2)
(S (NP I) (VP (V enjoyed) (NP my cookie)))
Trees can be compared for equality:
>>> tree == Tree.fromstring(str(tree))
True
>>> tree2 == Tree.fromstring(str(tree2))
True
>>> tree == tree2
False
>>> tree == Tree.fromstring(str(tree2))
False
>>> tree2 == Tree.fromstring(str(tree))
False
>>> tree != Tree.fromstring(str(tree))
False
>>> tree2 != Tree.fromstring(str(tree2))
False
>>> tree != tree2
True
>>> tree != Tree.fromstring(str(tree2))
True
>>> tree2 != Tree.fromstring(str(tree))
True
>>> tree < tree2 or tree > tree2
True
Tree Parsing
============
The class method `Tree.fromstring()` can be used to parse trees, and it
provides some additional options.
>>> tree = Tree.fromstring('(S (NP I) (VP (V enjoyed) (NP my cookie)))')
>>> print(tree)
(S (NP I) (VP (V enjoyed) (NP my cookie)))
When called on a subclass of `Tree`, it will create trees of that
type:
>>> tree = ImmutableTree.fromstring('(VP (V enjoyed) (NP my cookie))')
>>> print(tree)
(VP (V enjoyed) (NP my cookie))
>>> print(type(tree))
<class 'nltk.tree.ImmutableTree'>
>>> tree[1] = 'x'
Traceback (most recent call last):
. . .
ValueError: ImmutableTree may not be modified
>>> del tree[0]
Traceback (most recent call last):
. . .
ValueError: ImmutableTree may not be modified
The ``brackets`` parameter can be used to specify two characters that
should be used as brackets:
>>> print(Tree.fromstring('[S [NP I] [VP [V enjoyed] [NP my cookie]]]',
... brackets='[]'))
(S (NP I) (VP (V enjoyed) (NP my cookie)))
>>> print(Tree.fromstring('<S <NP I> <VP <V enjoyed> <NP my cookie>>>',
... brackets='<>'))
(S (NP I) (VP (V enjoyed) (NP my cookie)))
If ``brackets`` is not a string, or is not exactly two characters,
then `Tree.fromstring` raises an exception:
>>> Tree.fromstring('<VP <V enjoyed> <NP my cookie>>', brackets='')
Traceback (most recent call last):
. . .
TypeError: brackets must be a length-2 string
>>> Tree.fromstring('<VP <V enjoyed> <NP my cookie>>', brackets='<<>>')
Traceback (most recent call last):
. . .
TypeError: brackets must be a length-2 string
>>> Tree.fromstring('<VP <V enjoyed> <NP my cookie>>', brackets=12)
Traceback (most recent call last):
. . .
TypeError: brackets must be a length-2 string
>>> Tree.fromstring('<<NP my cookie>>', brackets=('<<','>>'))
Traceback (most recent call last):
. . .
TypeError: brackets must be a length-2 string
(We may add support for multi-character brackets in the future, in
which case the ``brackets=('<<','>>')`` example would start working.)
Whitespace brackets are not permitted:
>>> Tree.fromstring('(NP my cookie\n', brackets='(\n')
Traceback (most recent call last):
. . .
TypeError: whitespace brackets not allowed
If an invalid tree is given to Tree.fromstring, then it raises a
ValueError, with a description of the problem:
>>> Tree.fromstring('(NP my cookie) (NP my milk)')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected 'end-of-string' but got '(NP'
at index 15.
"...y cookie) (NP my mil..."
^
>>> Tree.fromstring(')NP my cookie(')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected '(' but got ')'
at index 0.
")NP my coo..."
^
>>> Tree.fromstring('(NP my cookie))')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected 'end-of-string' but got ')'
at index 14.
"...my cookie))"
^
>>> Tree.fromstring('my cookie)')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected '(' but got 'my'
at index 0.
"my cookie)"
^
>>> Tree.fromstring('(NP my cookie')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected ')' but got 'end-of-string'
at index 13.
"... my cookie"
^
>>> Tree.fromstring('')
Traceback (most recent call last):
. . .
ValueError: Tree.fromstring(): expected '(' but got 'end-of-string'
at index 0.
""
^
Trees with no children are supported:
>>> print(Tree.fromstring('(S)'))
(S )
>>> print(Tree.fromstring('(X (Y) (Z))'))
(X (Y ) (Z ))
Trees with an empty node label and no children are supported:
>>> print(Tree.fromstring('()'))
( )
>>> print(Tree.fromstring('(X () ())'))
(X ( ) ( ))
Trees with an empty node label and children are supported, but only if the
first child is not a leaf (otherwise, it will be treated as the node label).
>>> print(Tree.fromstring('((A) (B) (C))'))
( (A ) (B ) (C ))
>>> print(Tree.fromstring('((A) leaf)'))
( (A ) leaf)
>>> print(Tree.fromstring('(((())))'))
( ( ( ( ))))
The optional arguments `read_node` and `read_leaf` may be used to
transform the string values of nodes or leaves.
>>> print(Tree.fromstring('(A b (C d e) (F (G h i)))',
... read_node=lambda s: '<%s>' % s,
... read_leaf=lambda s: '"%s"' % s))
(<A> "b" (<C> "d" "e") (<F> (<G> "h" "i")))
These transformation functions are typically used when the node or
leaf labels should be parsed to a non-string value (such as a feature
structure). If node and leaf labels need to be able to include
whitespace, then you must also use the optional `node_pattern` and
`leaf_pattern` arguments.
>>> from nltk.featstruct import FeatStruct
>>> tree = Tree.fromstring('([cat=NP] [lex=the] [lex=dog])',
... read_node=FeatStruct, read_leaf=FeatStruct)
>>> tree.set_label(tree.label().unify(FeatStruct('[num=singular]')))
>>> print(tree)
([cat='NP', num='singular'] [lex='the'] [lex='dog'])
The optional argument ``remove_empty_top_bracketing`` can be used to
remove any top-level empty bracketing that occurs.
>>> print(Tree.fromstring('((S (NP I) (VP (V enjoyed) (NP my cookie))))',
... remove_empty_top_bracketing=True))
(S (NP I) (VP (V enjoyed) (NP my cookie)))
It will not remove a top-level empty bracketing with multiple children:
>>> print(Tree.fromstring('((A a) (B b))'))
( (A a) (B b))
Parented Trees
==============
`ParentedTree` is a subclass of `Tree` that automatically maintains
parent pointers for single-parented trees. Parented trees can be
created directly from a node label and a list of children:
>>> ptree = (
... ParentedTree('VP', [
... ParentedTree('VERB', ['saw']),
... ParentedTree('NP', [
... ParentedTree('DET', ['the']),
... ParentedTree('NOUN', ['dog'])])]))
>>> print(ptree)
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Parented trees can be created from strings using the classmethod
`ParentedTree.fromstring`:
>>> ptree = ParentedTree.fromstring('(VP (VERB saw) (NP (DET the) (NOUN dog)))')
>>> print(ptree)
(VP (VERB saw) (NP (DET the) (NOUN dog)))
>>> print(type(ptree))
<class 'nltk.tree.ParentedTree'>
Parented trees can also be created by using the classmethod
`ParentedTree.convert` to convert another type of tree to a parented
tree:
>>> tree = Tree.fromstring('(VP (VERB saw) (NP (DET the) (NOUN dog)))')
>>> ptree = ParentedTree.convert(tree)
>>> print(ptree)
(VP (VERB saw) (NP (DET the) (NOUN dog)))
>>> print(type(ptree))
<class 'nltk.tree.ParentedTree'>
.. clean-up:
>>> del tree
`ParentedTree`\ s should never be used in the same tree as `Tree`\ s
or `MultiParentedTree`\ s. Mixing tree implementations may result in
incorrect parent pointers and in `TypeError` exceptions:
>>> # Inserting a Tree in a ParentedTree gives an exception:
>>> ParentedTree('NP', [
... Tree('DET', ['the']), Tree('NOUN', ['dog'])])
Traceback (most recent call last):
. . .
TypeError: Can not insert a non-ParentedTree into a ParentedTree
>>> # inserting a ParentedTree in a Tree gives incorrect parent pointers:
>>> broken_tree = Tree('NP', [
... ParentedTree('DET', ['the']), ParentedTree('NOUN', ['dog'])])
>>> print(broken_tree[0].parent())
None
Parented Tree Methods
------------------------
In addition to all the methods defined by the `Tree` class, the
`ParentedTree` class adds six new methods whose values are
automatically updated whenver a parented tree is modified: `parent()`,
`parent_index()`, `left_sibling()`, `right_sibling()`, `root()`, and
`treeposition()`.
The `parent()` method contains a `ParentedTree`\ 's parent, if it has
one; and ``None`` otherwise. `ParentedTree`\ s that do not have
parents are known as "root trees."
>>> for subtree in ptree.subtrees():
... print(subtree)
... print(' Parent = %s' % subtree.parent())
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Parent = None
(VERB saw)
Parent = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(NP (DET the) (NOUN dog))
Parent = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(DET the)
Parent = (NP (DET the) (NOUN dog))
(NOUN dog)
Parent = (NP (DET the) (NOUN dog))
The `parent_index()` method stores the index of a tree in its parent's
child list. If a tree does not have a parent, then its `parent_index`
is ``None``.
>>> for subtree in ptree.subtrees():
... print(subtree)
... print(' Parent Index = %s' % subtree.parent_index())
... assert (subtree.parent() is None or
... subtree.parent()[subtree.parent_index()] is subtree)
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Parent Index = None
(VERB saw)
Parent Index = 0
(NP (DET the) (NOUN dog))
Parent Index = 1
(DET the)
Parent Index = 0
(NOUN dog)
Parent Index = 1
Note that ``ptree.parent().index(ptree)`` is *not* equivalent to
``ptree.parent_index()``. In particular, ``ptree.parent().index(ptree)``
will return the index of the first child of ``ptree.parent()`` that is
equal to ``ptree`` (using ``==``); and that child may not be
``ptree``:
>>> on_and_on = ParentedTree('CONJP', [
... ParentedTree('PREP', ['on']),
... ParentedTree('COJN', ['and']),
... ParentedTree('PREP', ['on'])])
>>> second_on = on_and_on[2]
>>> print(second_on.parent_index())
2
>>> print(second_on.parent().index(second_on))
0
The methods `left_sibling()` and `right_sibling()` can be used to get a
parented tree's siblings. If a tree does not have a left or right
sibling, then the corresponding method's value is ``None``:
>>> for subtree in ptree.subtrees():
... print(subtree)
... print(' Left Sibling = %s' % subtree.left_sibling())
... print(' Right Sibling = %s' % subtree.right_sibling())
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Left Sibling = None
Right Sibling = None
(VERB saw)
Left Sibling = None
Right Sibling = (NP (DET the) (NOUN dog))
(NP (DET the) (NOUN dog))
Left Sibling = (VERB saw)
Right Sibling = None
(DET the)
Left Sibling = None
Right Sibling = (NOUN dog)
(NOUN dog)
Left Sibling = (DET the)
Right Sibling = None
A parented tree's root tree can be accessed using the `root()`
method. This method follows the tree's parent pointers until it
finds a tree without a parent. If a tree does not have a parent, then
it is its own root:
>>> for subtree in ptree.subtrees():
... print(subtree)
... print(' Root = %s' % subtree.root())
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Root = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(VERB saw)
Root = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(NP (DET the) (NOUN dog))
Root = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(DET the)
Root = (VP (VERB saw) (NP (DET the) (NOUN dog)))
(NOUN dog)
Root = (VP (VERB saw) (NP (DET the) (NOUN dog)))
The `treeposition()` method can be used to find a tree's treeposition
relative to its root:
>>> for subtree in ptree.subtrees():
... print(subtree)
... print(' Tree Position = %s' % (subtree.treeposition(),))
... assert subtree.root()[subtree.treeposition()] is subtree
(VP (VERB saw) (NP (DET the) (NOUN dog)))
Tree Position = ()
(VERB saw)
Tree Position = (0,)
(NP (DET the) (NOUN dog))
Tree Position = (1,)
(DET the)
Tree Position = (1, 0)
(NOUN dog)
Tree Position = (1, 1)
Whenever a parented tree is modified, all of the methods described
above (`parent()`, `parent_index()`, `left_sibling()`, `right_sibling()`,
`root()`, and `treeposition()`) are automatically updated. For example,
if we replace ``ptree``\ 's subtree for the word "dog" with a new
subtree for "cat," the method values for both the "dog" subtree and the
"cat" subtree get automatically updated:
>>> # Replace the dog with a cat
>>> dog = ptree[1,1]
>>> cat = ParentedTree('NOUN', ['cat'])
>>> ptree[1,1] = cat
>>> # the noun phrase is no longer the dog's parent:
>>> print(dog.parent(), dog.parent_index(), dog.left_sibling())
None None None
>>> # dog is now its own root.
>>> print(dog.root())
(NOUN dog)
>>> print(dog.treeposition())
()
>>> # the cat's parent is now the noun phrase:
>>> print(cat.parent())
(NP (DET the) (NOUN cat))
>>> print(cat.parent_index())
1
>>> print(cat.left_sibling())
(DET the)
>>> print(cat.root())
(VP (VERB saw) (NP (DET the) (NOUN cat)))
>>> print(cat.treeposition())
(1, 1)
ParentedTree Regression Tests
-----------------------------
Keep track of all trees that we create (including subtrees) using this
variable:
>>> all_ptrees = []
Define a helper funciton to create new parented trees:
>>> def make_ptree(s):
... ptree = ParentedTree.convert(Tree.fromstring(s))
... all_ptrees.extend(t for t in ptree.subtrees()
... if isinstance(t, Tree))
... return ptree
Define a test function that examines every subtree in all_ptrees; and
checks that all six of its methods are defined correctly. If any
ptrees are passed as arguments, then they are printed.
>>> def pcheck(*print_ptrees):
... for ptree in all_ptrees:
... # Check ptree's methods.
... if ptree.parent() is not None:
... i = ptree.parent_index()
... assert ptree.parent()[i] is ptree
... if i > 0:
... assert ptree.left_sibling() is ptree.parent()[i-1]
... if i < (len(ptree.parent())-1):
... assert ptree.right_sibling() is ptree.parent()[i+1]
... assert len(ptree.treeposition()) > 0
... assert (ptree.treeposition() ==
... ptree.parent().treeposition() + (ptree.parent_index(),))
... assert ptree.root() is not ptree
... assert ptree.root() is not None
... assert ptree.root() is ptree.parent().root()
... assert ptree.root()[ptree.treeposition()] is ptree
... else:
... assert ptree.parent_index() is None
... assert ptree.left_sibling() is None
... assert ptree.right_sibling() is None
... assert ptree.root() is ptree
... assert ptree.treeposition() == ()
... # Check ptree's children's methods:
... for i, child in enumerate(ptree):
... if isinstance(child, Tree):
... # pcheck parent() & parent_index() methods
... assert child.parent() is ptree
... assert child.parent_index() == i
... # pcheck sibling methods
... if i == 0:
... assert child.left_sibling() is None
... else:
... assert child.left_sibling() is ptree[i-1]
... if i == len(ptree)-1:
... assert child.right_sibling() is None
... else:
... assert child.right_sibling() is ptree[i+1]
... if print_ptrees:
... print('ok!', end=' ')
... for ptree in print_ptrees: print(ptree)
... else:
... print('ok!')
Run our test function on a variety of newly-created trees:
>>> pcheck(make_ptree('(A)'))
ok! (A )
>>> pcheck(make_ptree('(A (B (C (D) (E f)) g) h)'))
ok! (A (B (C (D ) (E f)) g) h)
>>> pcheck(make_ptree('(A (B) (C c) (D d d) (E e e e))'))
ok! (A (B ) (C c) (D d d) (E e e e))
>>> pcheck(make_ptree('(A (B) (C (c)) (D (d) (d)) (E (e) (e) (e)))'))
ok! (A (B ) (C (c )) (D (d ) (d )) (E (e ) (e ) (e )))
Run our test function after performing various tree-modification
operations:
**__delitem__()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> e = ptree[0,0,1]
>>> del ptree[0,0,1]; pcheck(ptree); pcheck(e)
ok! (A (B (C (D ) (Q p)) g) h)
ok! (E f)
>>> del ptree[0,0,0]; pcheck(ptree)
ok! (A (B (C (Q p)) g) h)
>>> del ptree[0,1]; pcheck(ptree)
ok! (A (B (C (Q p))) h)
>>> del ptree[-1]; pcheck(ptree)
ok! (A (B (C (Q p))))
>>> del ptree[-100]
Traceback (most recent call last):
. . .
IndexError: index out of range
>>> del ptree[()]
Traceback (most recent call last):
. . .
IndexError: The tree position () may not be deleted.
>>> # With slices:
>>> ptree = make_ptree('(A (B c) (D e) f g (H i) j (K l))')
>>> b = ptree[0]
>>> del ptree[0:0]; pcheck(ptree)
ok! (A (B c) (D e) f g (H i) j (K l))
>>> del ptree[:1]; pcheck(ptree); pcheck(b)
ok! (A (D e) f g (H i) j (K l))
ok! (B c)
>>> del ptree[-2:]; pcheck(ptree)
ok! (A (D e) f g (H i))
>>> del ptree[1:3]; pcheck(ptree)
ok! (A (D e) (H i))
>>> ptree = make_ptree('(A (B c) (D e) f g (H i) j (K l))')
>>> del ptree[5:1000]; pcheck(ptree)
ok! (A (B c) (D e) f g (H i))
>>> del ptree[-2:1000]; pcheck(ptree)
ok! (A (B c) (D e) f)
>>> del ptree[-100:1]; pcheck(ptree)
ok! (A (D e) f)
>>> ptree = make_ptree('(A (B c) (D e) f g (H i) j (K l))')
>>> del ptree[1:-2:2]; pcheck(ptree)
ok! (A (B c) f (H i) j (K l))
**__setitem__()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> d, e, q = ptree[0,0]
>>> ptree[0,0,0] = 'x'; pcheck(ptree); pcheck(d)
ok! (A (B (C x (E f) (Q p)) g) h)
ok! (D )
>>> ptree[0,0,1] = make_ptree('(X (Y z))'); pcheck(ptree); pcheck(e)
ok! (A (B (C x (X (Y z)) (Q p)) g) h)
ok! (E f)
>>> ptree[1] = d; pcheck(ptree)
ok! (A (B (C x (X (Y z)) (Q p)) g) (D ))
>>> ptree[-1] = 'x'; pcheck(ptree)
ok! (A (B (C x (X (Y z)) (Q p)) g) x)
>>> ptree[-100] = 'y'
Traceback (most recent call last):
. . .
IndexError: index out of range
>>> ptree[()] = make_ptree('(X y)')
Traceback (most recent call last):
. . .
IndexError: The tree position () may not be assigned to.
>>> # With slices:
>>> ptree = make_ptree('(A (B c) (D e) f g (H i) j (K l))')
>>> b = ptree[0]
>>> ptree[0:0] = ('x', make_ptree('(Y)')); pcheck(ptree)
ok! (A x (Y ) (B c) (D e) f g (H i) j (K l))
>>> ptree[2:6] = (); pcheck(ptree); pcheck(b)
ok! (A x (Y ) (H i) j (K l))
ok! (B c)
>>> ptree[-2:] = ('z', 'p'); pcheck(ptree)
ok! (A x (Y ) (H i) z p)
>>> ptree[1:3] = [make_ptree('(X)') for x in range(10)]; pcheck(ptree)
ok! (A x (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) z p)
>>> ptree[5:1000] = []; pcheck(ptree)
ok! (A x (X ) (X ) (X ) (X ))
>>> ptree[-2:1000] = ['n']; pcheck(ptree)
ok! (A x (X ) (X ) n)
>>> ptree[-100:1] = [make_ptree('(U v)')]; pcheck(ptree)
ok! (A (U v) (X ) (X ) n)
>>> ptree[-1:] = (make_ptree('(X)') for x in range(3)); pcheck(ptree)
ok! (A (U v) (X ) (X ) (X ) (X ) (X ))
>>> ptree[1:-2:2] = ['x', 'y']; pcheck(ptree)
ok! (A (U v) x (X ) y (X ) (X ))
**append()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> ptree.append('x'); pcheck(ptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x)
>>> ptree.append(make_ptree('(X (Y z))')); pcheck(ptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x (X (Y z)))
**extend()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> ptree.extend(['x', 'y', make_ptree('(X (Y z))')]); pcheck(ptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)))
>>> ptree.extend([]); pcheck(ptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)))
>>> ptree.extend(make_ptree('(X)') for x in range(3)); pcheck(ptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)) (X ) (X ) (X ))
**insert()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> ptree.insert(0, make_ptree('(X (Y z))')); pcheck(ptree)
ok! (A (X (Y z)) (B (C (D ) (E f) (Q p)) g) h)
>>> ptree.insert(-1, make_ptree('(X (Y z))')); pcheck(ptree)
ok! (A (X (Y z)) (B (C (D ) (E f) (Q p)) g) (X (Y z)) h)
>>> ptree.insert(-4, make_ptree('(X (Y z))')); pcheck(ptree)
ok! (A (X (Y z)) (X (Y z)) (B (C (D ) (E f) (Q p)) g) (X (Y z)) h)
>>> # Note: as with ``list``, inserting at a negative index that
>>> # gives a position before the start of the list does *not*
>>> # raise an IndexError exception; it just inserts at 0.
>>> ptree.insert(-400, make_ptree('(X (Y z))')); pcheck(ptree)
ok! (A
(X (Y z))
(X (Y z))
(X (Y z))
(B (C (D ) (E f) (Q p)) g)
(X (Y z))
h)
**pop()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> ptree[0,0].pop(1); pcheck(ptree)
ParentedTree('E', ['f'])
ok! (A (B (C (D ) (Q p)) g) h)
>>> ptree[0].pop(-1); pcheck(ptree)
'g'
ok! (A (B (C (D ) (Q p))) h)
>>> ptree.pop(); pcheck(ptree)
'h'
ok! (A (B (C (D ) (Q p))))
>>> ptree.pop(-100)
Traceback (most recent call last):
. . .
IndexError: index out of range
**remove()**
>>> ptree = make_ptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> e = ptree[0,0,1]
>>> ptree[0,0].remove(ptree[0,0,1]); pcheck(ptree); pcheck(e)
ok! (A (B (C (D ) (Q p)) g) h)
ok! (E f)
>>> ptree[0,0].remove(make_ptree('(Q p)')); pcheck(ptree)
ok! (A (B (C (D )) g) h)
>>> ptree[0,0].remove(make_ptree('(Q p)'))
Traceback (most recent call last):
. . .
ValueError: ParentedTree('Q', ['p']) is not in list
>>> ptree.remove('h'); pcheck(ptree)
ok! (A (B (C (D )) g))
>>> ptree.remove('h');
Traceback (most recent call last):
. . .
ValueError: 'h' is not in list
>>> # remove() removes the first subtree that is equal (==) to the
>>> # given tree, which may not be the identical tree we give it:
>>> ptree = make_ptree('(A (X x) (Y y) (X x))')
>>> x1, y, x2 = ptree
>>> ptree.remove(ptree[-1]); pcheck(ptree)
ok! (A (Y y) (X x))
>>> print(x1.parent()); pcheck(x1)
None
ok! (X x)
>>> print(x2.parent())
(A (Y y) (X x))
Test that a tree can not be given multiple parents:
>>> ptree = make_ptree('(A (X x) (Y y) (Z z))')
>>> ptree[0] = ptree[1]
Traceback (most recent call last):
. . .
ValueError: Can not insert a subtree that already has a parent.
>>> pcheck()
ok!
[more to be written]
ImmutableParentedTree Regression Tests
--------------------------------------
>>> iptree = ImmutableParentedTree.convert(ptree)
>>> type(iptree)
<class 'nltk.tree.ImmutableParentedTree'>
>>> del iptree[0]
Traceback (most recent call last):
. . .
ValueError: ImmutableParentedTree may not be modified
>>> iptree.set_label('newnode')
Traceback (most recent call last):
. . .
ValueError: ImmutableParentedTree may not be modified
MultiParentedTree Regression Tests
----------------------------------
Keep track of all trees that we create (including subtrees) using this
variable:
>>> all_mptrees = []
Define a helper funciton to create new parented trees:
>>> def make_mptree(s):
... mptree = MultiParentedTree.convert(Tree.fromstring(s))
... all_mptrees.extend(t for t in mptree.subtrees()
... if isinstance(t, Tree))
... return mptree
Define a test function that examines every subtree in all_mptrees; and
checks that all six of its methods are defined correctly. If any
mptrees are passed as arguments, then they are printed.
>>> def mpcheck(*print_mptrees):
... def has(seq, val): # uses identity comparison
... for item in seq:
... if item is val: return True
... return False
... for mptree in all_mptrees:
... # Check mptree's methods.
... if len(mptree.parents()) == 0:
... assert len(mptree.left_siblings()) == 0
... assert len(mptree.right_siblings()) == 0
... assert len(mptree.roots()) == 1
... assert mptree.roots()[0] is mptree
... assert mptree.treepositions(mptree) == [()]
... left_siblings = right_siblings = ()
... roots = {id(mptree): 1}
... else:
... roots = dict((id(r), 0) for r in mptree.roots())
... left_siblings = mptree.left_siblings()
... right_siblings = mptree.right_siblings()
... for parent in mptree.parents():
... for i in mptree.parent_indices(parent):
... assert parent[i] is mptree
... # check left siblings
... if i > 0:
... for j in range(len(left_siblings)):
... if left_siblings[j] is parent[i-1]:
... del left_siblings[j]
... break
... else:
... assert 0, 'sibling not found!'
... # check ight siblings
... if i < (len(parent)-1):
... for j in range(len(right_siblings)):
... if right_siblings[j] is parent[i+1]:
... del right_siblings[j]
... break
... else:
... assert 0, 'sibling not found!'
... # check roots
... for root in parent.roots():
... assert id(root) in roots, 'missing root'
... roots[id(root)] += 1
... # check that we don't have any unexplained values
... assert len(left_siblings)==0, 'unexpected sibling'
... assert len(right_siblings)==0, 'unexpected sibling'
... for v in roots.values(): assert v>0, roots #'unexpected root'
... # check treepositions
... for root in mptree.roots():
... for treepos in mptree.treepositions(root):
... assert root[treepos] is mptree
... # Check mptree's children's methods:
... for i, child in enumerate(mptree):
... if isinstance(child, Tree):
... # mpcheck parent() & parent_index() methods
... assert has(child.parents(), mptree)
... assert i in child.parent_indices(mptree)
... # mpcheck sibling methods
... if i > 0:
... assert has(child.left_siblings(), mptree[i-1])
... if i < len(mptree)-1:
... assert has(child.right_siblings(), mptree[i+1])
... if print_mptrees:
... print('ok!', end=' ')
... for mptree in print_mptrees: print(mptree)
... else:
... print('ok!')
Run our test function on a variety of newly-created trees:
>>> mpcheck(make_mptree('(A)'))
ok! (A )
>>> mpcheck(make_mptree('(A (B (C (D) (E f)) g) h)'))
ok! (A (B (C (D ) (E f)) g) h)
>>> mpcheck(make_mptree('(A (B) (C c) (D d d) (E e e e))'))
ok! (A (B ) (C c) (D d d) (E e e e))
>>> mpcheck(make_mptree('(A (B) (C (c)) (D (d) (d)) (E (e) (e) (e)))'))
ok! (A (B ) (C (c )) (D (d ) (d )) (E (e ) (e ) (e )))
>>> subtree = make_mptree('(A (B (C (D) (E f)) g) h)')
Including some trees that contain multiple parents:
>>> mpcheck(MultiParentedTree('Z', [subtree, subtree]))
ok! (Z (A (B (C (D ) (E f)) g) h) (A (B (C (D ) (E f)) g) h))
Run our test function after performing various tree-modification
operations (n.b., these are the same tests that we ran for
`ParentedTree`, above; thus, none of these trees actually *uses*
multiple parents.)
**__delitem__()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> e = mptree[0,0,1]
>>> del mptree[0,0,1]; mpcheck(mptree); mpcheck(e)
ok! (A (B (C (D ) (Q p)) g) h)
ok! (E f)
>>> del mptree[0,0,0]; mpcheck(mptree)
ok! (A (B (C (Q p)) g) h)
>>> del mptree[0,1]; mpcheck(mptree)
ok! (A (B (C (Q p))) h)
>>> del mptree[-1]; mpcheck(mptree)
ok! (A (B (C (Q p))))
>>> del mptree[-100]
Traceback (most recent call last):
. . .
IndexError: index out of range
>>> del mptree[()]
Traceback (most recent call last):
. . .
IndexError: The tree position () may not be deleted.
>>> # With slices:
>>> mptree = make_mptree('(A (B c) (D e) f g (H i) j (K l))')
>>> b = mptree[0]
>>> del mptree[0:0]; mpcheck(mptree)
ok! (A (B c) (D e) f g (H i) j (K l))
>>> del mptree[:1]; mpcheck(mptree); mpcheck(b)
ok! (A (D e) f g (H i) j (K l))
ok! (B c)
>>> del mptree[-2:]; mpcheck(mptree)
ok! (A (D e) f g (H i))
>>> del mptree[1:3]; mpcheck(mptree)
ok! (A (D e) (H i))
>>> mptree = make_mptree('(A (B c) (D e) f g (H i) j (K l))')
>>> del mptree[5:1000]; mpcheck(mptree)
ok! (A (B c) (D e) f g (H i))
>>> del mptree[-2:1000]; mpcheck(mptree)
ok! (A (B c) (D e) f)
>>> del mptree[-100:1]; mpcheck(mptree)
ok! (A (D e) f)
>>> mptree = make_mptree('(A (B c) (D e) f g (H i) j (K l))')
>>> del mptree[1:-2:2]; mpcheck(mptree)
ok! (A (B c) f (H i) j (K l))
**__setitem__()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> d, e, q = mptree[0,0]
>>> mptree[0,0,0] = 'x'; mpcheck(mptree); mpcheck(d)
ok! (A (B (C x (E f) (Q p)) g) h)
ok! (D )
>>> mptree[0,0,1] = make_mptree('(X (Y z))'); mpcheck(mptree); mpcheck(e)
ok! (A (B (C x (X (Y z)) (Q p)) g) h)
ok! (E f)
>>> mptree[1] = d; mpcheck(mptree)
ok! (A (B (C x (X (Y z)) (Q p)) g) (D ))
>>> mptree[-1] = 'x'; mpcheck(mptree)
ok! (A (B (C x (X (Y z)) (Q p)) g) x)
>>> mptree[-100] = 'y'
Traceback (most recent call last):
. . .
IndexError: index out of range
>>> mptree[()] = make_mptree('(X y)')
Traceback (most recent call last):
. . .
IndexError: The tree position () may not be assigned to.
>>> # With slices:
>>> mptree = make_mptree('(A (B c) (D e) f g (H i) j (K l))')
>>> b = mptree[0]
>>> mptree[0:0] = ('x', make_mptree('(Y)')); mpcheck(mptree)
ok! (A x (Y ) (B c) (D e) f g (H i) j (K l))
>>> mptree[2:6] = (); mpcheck(mptree); mpcheck(b)
ok! (A x (Y ) (H i) j (K l))
ok! (B c)
>>> mptree[-2:] = ('z', 'p'); mpcheck(mptree)
ok! (A x (Y ) (H i) z p)
>>> mptree[1:3] = [make_mptree('(X)') for x in range(10)]; mpcheck(mptree)
ok! (A x (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) (X ) z p)
>>> mptree[5:1000] = []; mpcheck(mptree)
ok! (A x (X ) (X ) (X ) (X ))
>>> mptree[-2:1000] = ['n']; mpcheck(mptree)
ok! (A x (X ) (X ) n)
>>> mptree[-100:1] = [make_mptree('(U v)')]; mpcheck(mptree)
ok! (A (U v) (X ) (X ) n)
>>> mptree[-1:] = (make_mptree('(X)') for x in range(3)); mpcheck(mptree)
ok! (A (U v) (X ) (X ) (X ) (X ) (X ))
>>> mptree[1:-2:2] = ['x', 'y']; mpcheck(mptree)
ok! (A (U v) x (X ) y (X ) (X ))
**append()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> mptree.append('x'); mpcheck(mptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x)
>>> mptree.append(make_mptree('(X (Y z))')); mpcheck(mptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x (X (Y z)))
**extend()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> mptree.extend(['x', 'y', make_mptree('(X (Y z))')]); mpcheck(mptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)))
>>> mptree.extend([]); mpcheck(mptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)))
>>> mptree.extend(make_mptree('(X)') for x in range(3)); mpcheck(mptree)
ok! (A (B (C (D ) (E f) (Q p)) g) h x y (X (Y z)) (X ) (X ) (X ))
**insert()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> mptree.insert(0, make_mptree('(X (Y z))')); mpcheck(mptree)
ok! (A (X (Y z)) (B (C (D ) (E f) (Q p)) g) h)
>>> mptree.insert(-1, make_mptree('(X (Y z))')); mpcheck(mptree)
ok! (A (X (Y z)) (B (C (D ) (E f) (Q p)) g) (X (Y z)) h)
>>> mptree.insert(-4, make_mptree('(X (Y z))')); mpcheck(mptree)
ok! (A (X (Y z)) (X (Y z)) (B (C (D ) (E f) (Q p)) g) (X (Y z)) h)
>>> # Note: as with ``list``, inserting at a negative index that
>>> # gives a position before the start of the list does *not*
>>> # raise an IndexError exception; it just inserts at 0.
>>> mptree.insert(-400, make_mptree('(X (Y z))')); mpcheck(mptree)
ok! (A
(X (Y z))
(X (Y z))
(X (Y z))
(B (C (D ) (E f) (Q p)) g)
(X (Y z))
h)
**pop()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> mptree[0,0].pop(1); mpcheck(mptree)
MultiParentedTree('E', ['f'])
ok! (A (B (C (D ) (Q p)) g) h)
>>> mptree[0].pop(-1); mpcheck(mptree)
'g'
ok! (A (B (C (D ) (Q p))) h)
>>> mptree.pop(); mpcheck(mptree)
'h'
ok! (A (B (C (D ) (Q p))))
>>> mptree.pop(-100)
Traceback (most recent call last):
. . .
IndexError: index out of range
**remove()**
>>> mptree = make_mptree('(A (B (C (D) (E f) (Q p)) g) h)')
>>> e = mptree[0,0,1]
>>> mptree[0,0].remove(mptree[0,0,1]); mpcheck(mptree); mpcheck(e)
ok! (A (B (C (D ) (Q p)) g) h)
ok! (E f)
>>> mptree[0,0].remove(make_mptree('(Q p)')); mpcheck(mptree)
ok! (A (B (C (D )) g) h)
>>> mptree[0,0].remove(make_mptree('(Q p)'))
Traceback (most recent call last):
. . .
ValueError: MultiParentedTree('Q', ['p']) is not in list
>>> mptree.remove('h'); mpcheck(mptree)
ok! (A (B (C (D )) g))
>>> mptree.remove('h');
Traceback (most recent call last):
. . .
ValueError: 'h' is not in list
>>> # remove() removes the first subtree that is equal (==) to the
>>> # given tree, which may not be the identical tree we give it:
>>> mptree = make_mptree('(A (X x) (Y y) (X x))')
>>> x1, y, x2 = mptree
>>> mptree.remove(mptree[-1]); mpcheck(mptree)
ok! (A (Y y) (X x))
>>> print([str(p) for p in x1.parents()])
[]
>>> print([str(p) for p in x2.parents()])
['(A (Y y) (X x))']
ImmutableMultiParentedTree Regression Tests
-------------------------------------------
>>> imptree = ImmutableMultiParentedTree.convert(mptree)
>>> type(imptree)
<class 'nltk.tree.ImmutableMultiParentedTree'>
>>> del imptree[0]
Traceback (most recent call last):
. . .
ValueError: ImmutableMultiParentedTree may not be modified
>>> imptree.set_label('newnode')
Traceback (most recent call last):
. . .
ValueError: ImmutableMultiParentedTree may not be modified
ProbabilisticTree Regression Tests
----------------------------------
>>> prtree = ProbabilisticTree("S", [ProbabilisticTree("NP", ["N"], prob=0.3)], prob=0.6)
>>> print(prtree)
(S (NP N)) (p=0.6)
>>> import copy
>>> prtree == copy.deepcopy(prtree) == prtree.copy(deep=True) == prtree.copy()
True
>>> prtree[0] is prtree.copy()[0]
True
>>> prtree[0] is prtree.copy(deep=True)[0]
False
>>> imprtree = ImmutableProbabilisticTree.convert(prtree)
>>> type(imprtree)
<class 'nltk.tree.ImmutableProbabilisticTree'>
>>> del imprtree[0]
Traceback (most recent call last):
. . .
ValueError: ImmutableProbabilisticTree may not be modified
>>> imprtree.set_label('newnode')
Traceback (most recent call last):
. . .
ValueError: ImmutableProbabilisticTree may not be modified
Squashed Bugs
=============
This used to discard the ``(B b)`` subtree (fixed in svn 6270):
>>> print(Tree.fromstring('((A a) (B b))'))
( (A a) (B b))