Question

I am parsing JSON that stores various code snippets and I am first building a dictionary of languages used by these snippets:

snippets = {'python': {}, 'text': {}, 'php': {}, 'js': {}}

Then when looping through the JSON I’m wanting add the information about the snippet into its own dictionary to the dictionary listed above. For example, if I had a JS snippet – the end result would be:

snippets = {'js': 
                 {"title":"Script 1","code":"code here", "id":"123456"}
                 {"title":"Script 2","code":"code here", "id":"123457"}
}

Not to muddy the waters – but in PHP working on a multi-dimensional array I would just do the following (I am lookng for something similiar):

snippets['js'][] = array here

I know I saw one or two people talking about how to create a multidimensional dictionary – but can’t seem to track down adding a dictionary to a dictionary within python. Thanks for the help.

Answer 1

This is called autovivification:

You can do it with defaultdict

def tree():
    return collections.defaultdict(tree)

d = tree()
d['js']['title'] = 'Script1'

If the idea is to have lists, you can do:

d = collections.defaultdict(list)
d['js'].append({'foo': 'bar'})
d['js'].append({'other': 'thing'})

The idea for defaultdict it to create automatically the element when the key is accessed. BTW, for this simple case, you can simply do:

d = {}
d['js'] = [{'foo': 'bar'}, {'other': 'thing'}]