Read a dict of dicts in a list

Question

I would like to read all source for an id in a json file that looks like this. One id can have two sources, sometimes zero sources.

[ 
    {
        "trailers": {
            "quicktime": [], 
            "youtube": [
                {
                    "source": "source1", 
                    "type": "Trailer", 
                    "name": "Vf", 
                    "size": "HD"
                },
        {
                    "source": "source2", 
                    "type": "Trailer", 
                    "name": "Vf", 
                    "size": "HD"
                }
            ], 
            "id": 57417
        }, 

    {
        "trailers": {
            "quicktime": [], 
            "youtube": [], 
            "id": 57418
        }
]

I tried many solutions and I stopped in this one , and it doesn't work also :

from itertools import chain
trailers = {}
for item in j:        
    if item['trailers']:
        e = item['trailers']
        for k,value in e.iteritems():
            if k == "youtube":
                for each_dict in value:
                    for innerk, innerv in each_dict.iteritems():
                        if innerk == "source" :
                            trailers = dict(trailers.items() , {'trailer' : 'None'}.iteritems())                                                                
                        else:
                            trailers = {'trailer' : 'None'}

Edit : I would like to see this result :

57417, source1, source2
57418, None

Do you have suggestions ?

What are you trying to achieve? Find all trailers on YouTube? — Martijn Pieters, Dec 18 '13 at 18:15
The output that I would like to see is : `57417, source1, source2` ans `57418, None` Of course I imported `json` and everything works except this part . — 4m1nh4j1, Dec 18 '13 at 18:18
You're a bit vague in describing what you want. I have a hunch that your question is probably similar to the question posed [here](http://stackoverflow.com/questions/14048948/how-can-i-use-python-finding-particular-json-value-by-key). — nfazzio, Dec 18 '13 at 18:18
@4m1nh4j1: You need to be **explicit** in what you want. You want to map trailer `id` keys to a list of sources? Only YouTube sources or also Quicktime? — Martijn Pieters, Dec 18 '13 at 18:19
There are brace imbalences in the json that you've posted. Please fix — inspectorG4dget, Dec 18 '13 at 18:20
Yes, map trailer id keys to a list `id` sources , only with youtube. — 4m1nh4j1, Dec 18 '13 at 18:21
I'd not set an empty result to `None`; make it a consistent format, and an empty list. — Martijn Pieters, Dec 18 '13 at 18:21

Martijn Pieters · Accepted Answer · 2013-12-18T18:27:20.867

0

Finding all trailers on YouTube:

trailers = {film['trailers']['id']: [source['source'] for source in film['trailers'].get('youtube', [])] 
            for film in j}

This produces:

>>> {film['trailers']['id']: [source['source'] for source in film['trailers'].get('youtube', [])] 
...             for film in j}
{57417: ['source1', 'source2'], 57418: []}

edited Dec 18 '13 at 18:27

answered Dec 18 '13 at 18:22

Martijn Pieters

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@SteveJessop: Nested list comprehension there. But I was tripping over what is a list and what is a dictionary there first. All working now. – Martijn Pieters Dec 18 '13 at 18:29

Read a dict of dicts in a list

1 Answers1