If you like XPath and JSON, too, you can use my just updated Xidel (http://www.videlibri.de/xidel.html) to run XPath queries on JSON.

It can do transformations, where you write the output structure, and then pick the values from the input JSON. E.g. to transform from {"a": [{"b": 123}, {"b": 456}]} to {"c": [123,456]}, you could write an XPath expression {"c": a/b }