Can't filter selections on root node

[pkerpedjiev]

Consider the correctly working code below. It simply selects the elements where x<2.

>>> a = {"data": [{'x': 1}, {'x':2}]}
>>> tree = objectpath.Tree(a)
>>> list(tree.execute('$.data[@.x < 2]'))
[{'x': 1}]

Now if we remove data and make the list the root node, it doesn't work:

>>> a = [{'x': 1}, {'x':2}]
>>> tree = objectpath.Tree(a)
>>> list(tree.execute('$[@.x < 2]'))
[{'x': 1}, {'x': 2}]

Is there a reason why this is so? Should it be so? Wouldn't it make conceptual sense to be able to do the same filters on the root node as on child nodes?

[adriank]

$ needs to be postponed by . or .. and then attribute name or wildcard.

list(tree.execute('$.*[@.x < 2]')) should work. :)

[pkerpedjiev]

Thanks for the quick response! It does indeed work.

But shouldn't the version I posted also work?

If $.data[@.x < 2] refers to all entries in $.data where x < 2, then shouldn't $[@.x < 2] logically refer to all entries in $ where x < 2?

[adriank]

For me $[@ looks like brainfuck. :)

If you like to change this behavior go here: https://github.com/adriank/ObjectPath/blob/master/objectpath/core/parser.py#L274 and comment lines: 274, 276-278. Namespaces doesn't work ATM so nothing will break.