Xpath like query for nested python dictionaries

There is an easier way to do this now.

http://github.com/akesterson/dpath-python

$ easy_install dpath
>>> dpath.util.search(YOUR_DICTIONARY, "morefoo/morebar")

... done. Or if you don't like getting your results back in a view (merged dictionary that retains the paths), yield them instead:

$ easy_install dpath
>>> for (path, value) in dpath.util.search(YOUR_DICTIONARY, "morefoo/morebar", yielded=True)

... and done. 'value' will hold {'bacon': 'foobar'} in that case.

One of the best libraries I've been able to identify, which, in addition, is very actively developed, is an extracted project from boto: JMESPath. It has a very powerful syntax of doing things that would normally take pages of code to express.

Here are some examples:

search('foo | bar', {"foo": {"bar": "baz"}}) -> "baz"
search('foo[*].bar | [0]', {
    "foo": [{"bar": ["first1", "second1"]},
            {"bar": ["first2", "second2"]}]}) -> ["first1", "second1"]
search('foo | [0]', {"foo": [0, 1, 2]}) -> [0]

Not exactly beautiful, but you might use sth like

def xpath_get(mydict, path):
    elem = mydict
    try:
        for x in path.strip("/").split("/"):
            elem = elem.get(x)
    except:
        pass

    return elem

This doesn't support xpath stuff like indices, of course ... not to mention the / key trap unutbu indicated.