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94 lines
2.6 KiB
94 lines
2.6 KiB
# -*- coding: utf-8 -*-
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class Walker(object):
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def __init__(self):
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"""Walk from one node to another."""
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super(Walker, self).__init__()
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def walk(self, start, end):
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"""
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Walk from `start` node to `end` node.
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Returns:
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(upwards, common, downwards): `upwards` is a list of nodes to go upward to.
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`common` top node. `downwards` is a list of nodes to go downward to.
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Raises:
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WalkError: on no common root node.
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>>> from anytree import Node, RenderTree, AsciiStyle
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>>> f = Node("f")
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>>> b = Node("b", parent=f)
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>>> a = Node("a", parent=b)
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>>> d = Node("d", parent=b)
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>>> c = Node("c", parent=d)
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>>> e = Node("e", parent=d)
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>>> g = Node("g", parent=f)
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>>> i = Node("i", parent=g)
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>>> h = Node("h", parent=i)
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>>> print(RenderTree(f, style=AsciiStyle()))
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Node('/f')
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|-- Node('/f/b')
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| |-- Node('/f/b/a')
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| +-- Node('/f/b/d')
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| |-- Node('/f/b/d/c')
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| +-- Node('/f/b/d/e')
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+-- Node('/f/g')
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+-- Node('/f/g/i')
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+-- Node('/f/g/i/h')
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Create a walker:
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>>> w = Walker()
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This class is made for walking:
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>>> w.walk(f, f)
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((), Node('/f'), ())
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>>> w.walk(f, b)
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((), Node('/f'), (Node('/f/b'),))
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>>> w.walk(b, f)
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((Node('/f/b'),), Node('/f'), ())
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>>> w.walk(h, e)
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((Node('/f/g/i/h'), Node('/f/g/i'), Node('/f/g')), Node('/f'), (Node('/f/b'), Node('/f/b/d'), Node('/f/b/d/e')))
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>>> w.walk(d, e)
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((), Node('/f/b/d'), (Node('/f/b/d/e'),))
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For a proper walking the nodes need to be part of the same tree:
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>>> w.walk(Node("a"), Node("b"))
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Traceback (most recent call last):
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...
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anytree.walker.WalkError: Node('/a') and Node('/b') are not part of the same tree.
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"""
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s = start.path
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e = end.path
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if start.root != end.root:
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msg = "%r and %r are not part of the same tree." % (start, end)
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raise WalkError(msg)
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# common
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c = Walker.__calc_common(s, e)
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assert c[0] is start.root
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len_c = len(c)
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# up
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if start is c[-1]:
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up = tuple()
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else:
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up = tuple(reversed(s[len_c:]))
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# down
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if end is c[-1]:
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down = tuple()
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else:
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down = e[len_c:]
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return up, c[-1], down
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@staticmethod
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def __calc_common(s, e):
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return tuple([si for si, ei in zip(s, e) if si is ei])
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class WalkError(RuntimeError):
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"""Walk Error."""
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