configtree.tree
¶

class
configtree.tree.
ITree
¶ Abstract base class for
Tree
andBranchProxy
.Useful for type checking:
>>> tree = Tree({'x.y': 1}) >>> tree Tree({'x.y': 1}) >>> isinstance(tree, ITree) True >>> tree['x'] BranchProxy('x'): {'y': 1} >>> isinstance(tree, ITree) True

class
configtree.tree.
Tree
(data=None)¶ Tree is a dictionary like object, which supports nested keys.
Examples:
>>> tree = Tree() >>> tree['a.b.c'] = 1 >>> tree['a'] == {'b.c': 1} True >>> tree['a.b'] == {'c': 1} True >>> tree['a']['b'] == {'c': 1} True >>> tree['a.b']['d'] = 2 >>> tree['a.b'] == {'c': 1, 'd': 2} True
The tree object is unable to create an empty branch on demand:
>>> branch = tree['x.y'] # DOCTEST: +ellipsis Traceback (most recent call last): ... KeyError: 'x.y'
Use
branch()
for this purposes. It explicitly creates aBranchProxy
object tied to the specified key:>>> branch = tree.branch('x.y') >>> branch['z'] = 3 >>> tree == {'a.b.c': 1, 'a.b.d': 2, 'x.y.z': 3} True
An empty branch automatically collapses from the Tree:
>>> del branch['z'] >>> 'x.y' in tree False
The tree object doesn’t perform any implicit type inspection and conversion. It means what you put into the tree is what you will get from one later. Even when you put one branch to another, the Tree won’t create a copy:
>>> tree['x'] = tree['a'] >>> tree['x.b.c'] # DOCTEST: +ellipsis Traceback (most recent call last): ... KeyError: 'x.b.c' >>> tree['x']['b.c'] 1 >>> tree['x']['b.c'] = 3 >>> tree['a.b.c'] 3
It’s a road to debug hell, don’t follow it. If you want to copy a branch, use
update()
method.>>> tree = Tree({'a.b.c': 1}) >>> tree.branch('x').update(tree['a']) >>> tree == {'a.b.c': 1, 'x.b.c': 1} True >>> tree['x.b.c'] = 3 >>> tree == {'a.b.c': 1, 'x.b.c': 3} True
The tree object provides complete
collections.abc.MutableMapping
interface. So that it can be used where builtindict
is expected. Additionally, the following methods are available that extend class functionality.
branch
(key)¶ Returns a
BranchProxy
object for specifiedkey

rare_keys
()¶ Returns an iterator over the first level keys.
>>> tree = Tree({'a.b.c': 1, 'k': 2, 'x.y.z': 3}) >>> sorted(list(tree.rare_keys())) == ['a', 'k', 'x'] True

rare_values
()¶ Returns an iterator over the first level values.
See
rare_keys()
.

rare_items
()¶ Returns an iterator over the first level items.
See
rare_keys()

copy
()¶ Returns a shallow copy of the tree. The result has the same type.

rare_copy
()¶ Returns a rarefied copy of the tree.
>>> tree = Tree({'x.y.z': 1}) >>> tree.rare_copy() {'x': {'y': {'z': 1}}}


class
configtree.tree.
BranchProxy
(key, owner)¶ Branch Proxy is a helper object. This kind of object is created on demand when you expose an intermediate key of the
Tree
object:>>> tree = Tree({'a.b.c': 1}) >>> branch = tree['a.b'] >>> isinstance(branch, BranchProxy) True
The class methods are similar to
Tree
ones. Each method is just proxied to corresponding owner’s one.

configtree.tree.
flatten
(d)¶ Generator which flattens out passed nested mapping objects.
It’s useful in combination with
Tree
constructor orTree.update()
:>>> nested = {'a': {'b': {'c': 1}}} >>> Tree(nested) # without flatten Tree({'a': {'b': {'c': 1}}}) >>> Tree(flatten(nested)) # with flatten Tree({'a.b.c': 1})