scrape v3.1.0 Scrape.Tools.Tree
Utility module for interacting with nested Map structures, here called "tree".
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Link to this section Functions
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find(tree, selector)
Attempts to get a nested value from the tree using a string selector syntax.
Returns nil if nothing matches the selector or all matching results.
Examples
iex> Tree.find(%{"a" => %{"b" => "c"}}, "a")
%{"b" => "c"}
iex> Tree.find(%{"a" => %{"b" => "c"}}, "a.b")
"c"
iex> Tree.find(%{"a" => %{"b" => "c"}}, "unknown")
nil
iex> Tree.find(%{"a" => [%{"b" => "c"}]}, "a.b")
["c"]
iex> Tree.find(%{"a" => [%{"b" => [%{"c" => "d"}]}]}, "a.b.c")
["d"]
iex> Tree.find(%{"a" => [%{"b" => "c"}, %{"b" => "c"}]}, "a.b")
["c", "c"]
iex> Tree.find(%{"a" => [%{"b" => [%{"c" => "d"}]}]}, "a.*.c")
["d"]
iex> Tree.find(%{"hello" => "world"}, "~ell")
["world"]
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find_all(tree, selectors)
Applies find/2 to all given selectors and combines the result.
Examples
iex> Tree.find_all(%{"a" => "b", "c" => "d"}, ["a", "c"])
["b", "d"]
iex> Tree.find_all(%{"a" => "b", "c" => "d"}, ["a", "z"])
["b"]
iex> Tree.find_all(%{"a" => "b", "c" => "d"}, ["x", "y"])
[]
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first(tree, list)
Attempts all queries until one returns a non-nil result or nil.
Examples
iex> Tree.first(%{"hello" => "world"}, ["unknown"])
nil
iex> Tree.first(%{"hello" => "world"}, ["unknown", "hello"])
"world"
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from_xml_string(xml)
Transform a given xml string into a tree.
The string must be utf-8 encoded. It will be sanitized via Floki and the xml declaration header will be stripped.
Examples
iex> Tree.from_xml_string("<feed><item>abc</item></feed>")
%{"feed" => %{"item" => "abc"}}