/usr/share/pyshared/enthought/util/tree.py is in python-enthoughtbase 3.1.0-2build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | 'Functions on trees, that is, nested sequences.'
from enthought.util.functional import partial
from enthought.util.sequence import all, any, concat, is_sequence
def is_fork(x, leaves=()):
'Test whether a tree is a fork (instead of a leaf).'
return is_sequence(x) and not isinstance(x, leaves)
def flatten(tree, leaves=()):
''' Flatten a tree, that is, recursively concatenate nested sequences.
>>> flatten([1, [[2, 3], 4, 5], [[[[6]]]]])
[1, 2, 3, 4, 5, 6]
>>> mixed = [1, [[2], 3], (4, 5), [(6,)], 'abc']
>>> flatten(mixed)
[1, 2, 3, 4, 5, 6, 'a', 'b', 'c']
>>> flatten(mixed, leaves=(str,))
[1, 2, 3, 4, 5, 6, 'abc']
>>> flatten(mixed, leaves=(str, tuple))
[1, 2, 3, (4, 5), (6,), 'abc']
>>> flatten([])
[]
>>> flatten(1)
[1]
'''
# Pass leaf types around, avoiding infinite regress on strings
_is_fork = partial(is_fork, leaves=leaves)
if isinstance(tree, basestring):
leaves += (basestring,)
_flatten = partial(flatten, leaves=leaves)
if not _is_fork(tree):
return [tree]
else:
return concat(_flatten(n) for n in tree)
def tree_map(f, tree, leaves=()):
''' Map a function over the leaves of a tree.
>>> tree_map(str, [1,[2,3]])
['1', ['2', '3']]
>>> tree_map(len, ['foo', ['x', 'asdf']])
[[1, 1, 1], [[1], [1, 1, 1, 1]]]
>>> tree_map(len, ['foo', ['x', 'asdf']], leaves=(str,))
[3, [1, 4]]
'''
# Pass leaf types around, avoiding infinite regress on strings
_is_fork = partial(is_fork, leaves=leaves)
if isinstance(tree, basestring):
leaves += (basestring,)
_tree_map = partial(tree_map, leaves=leaves)
if not _is_fork(tree):
return f(tree)
else:
seq = isinstance(tree, tuple) and tuple or list
return seq([ _tree_map(f,n) for n in tree ])
def tree_zip(*trees, **kw):
''' Zip recursively.
Returns nested lists with tuples at the bottom.
>>> tree_zip([1,[2,3]], [5,[6,7]])
[(1, 5), [(2, 6), (3, 7)]]
>>> tree_zip([1,[2,3]], [5,[6,7]], ['a',['b','c']])
[(1, 5, 'a'), [(2, 6, 'b'), (3, 7, 'c')]]
>>> tree_zip('foo', 'bar')
[('f', 'b'), ('o', 'a'), ('o', 'r')]
>>> tree_zip(['foo'], ['bar'])
[[('f', 'b'), ('o', 'a'), ('o', 'r')]]
>>> tree_zip(['foo'], ['bar'], leaves=(str,))
[('foo', 'bar')]
>>> tree_zip('foo', ['bar'])
[('f', 'bar')]
>>> tree_zip('foo', ['bar'], leaves=(str,))
('foo', ['bar'])
>>> tree_zip(1, 2)
(1, 2)
>>> tree_zip([1,[2,3]], [5,6,7,8], [['a','b'],['c','d']])
[(1, 5, ['a', 'b']), ([2, 3], 6, ['c', 'd'])]
'''
# (Default arguments)
leaves = kw.get('leaves', ())
# Pass leaf types around, avoiding infinite regress on strings
_is_fork = partial(is_fork, leaves=leaves)
if any(isinstance(t, basestring) for t in trees):
leaves += (basestring,)
_tree_zip = partial(tree_zip, leaves=leaves)
if not all(_is_fork(t) for t in trees):
return trees
else:
return [ _tree_zip(*neighbors) for neighbors in zip(*trees) ]
def tree_embeds(t, u, leaves=()):
''' ...
>>> tree_embeds([1], [2])
True
>>> tree_embeds([1], [1,2])
False
>>> tree_embeds([1], [[1,2]])
True
>>> tree_embeds([1,[2,3]], [[True, False], 'ab'])
True
>>> tree_embeds([1,[2,3]], [[True, False], 'ab'], leaves=(str,))
False
>>> tree_embeds([], [1,2,3])
False
>>> tree_embeds(1, [1,2,3])
True
'''
# Pass leaf types around, avoiding infinite regress on strings
_is_fork = partial(is_fork, leaves=leaves)
if isinstance(t, basestring) or isinstance(u, basestring):
leaves += (basestring,)
_tree_embeds = partial(tree_embeds, leaves=leaves)
if not _is_fork(t):
return True
else:
return (_is_fork(u) and len(list(t)) == len(list(u)) and
all(_tree_embeds(n,m) for n,m in zip(t,u)))
def tree_shape(tree, leaves=()):
''' The shape of a tree expressed as nested tuples of nothing.
>>> tree_shape([1,[2,3]]) == tree_shape([True, 'ab'])
True
>>> tree_shape([1,[2,3]])
((), ((), ()))
>>> tree_shape(['ab', ['c', 'd']])
(((), ()), (((),), ((),)))
>>> tree_shape(['ab', ['c', 'd']], leaves=(str,))
((), ((), ()))
>>> tree_shape(1)
()
'''
# Pass leaf types around, avoiding infinite regress on strings
_is_fork = partial(is_fork, leaves=leaves)
if isinstance(tree, basestring):
leaves += (basestring,)
_tree_shape = partial(tree_shape, leaves=leaves)
if not _is_fork(tree):
return ()
else:
return tuple(_tree_shape(n) for n in tree)
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