CODEWITHSUNDEEP
pythonlistpython-2.7dictionaryfilter
user3739223
user3739223

Reputation:

Filter list of dictionaries in python

So, I need to build a filter that basically takes the following information...

dictlist = [{'ext': 'mp4',
                 'height': 480,
                 'id', 'pies'},
                {'ext': 'webm',
                 'height': 360,
                 'id', 'pies2'},
                {'ext': 'mp4',
                 'height': 360,
                 'id', 'charles1'},
                {'ext': 'mp4',
                 'height': 720,
                 'id', 'tucker'}]

(there's more stuff there, but this is simplified)

And then outputs the id of the element that is both an mp4 (or whatever I want. I'm aiming for a function or, alternative, to use built-in stuff to be more python-y if it exists) and has the highest height below a value.

For example, I'd like to build a function that is similar to...

def getmestuff(listofdics, extrequired, heightmax):
    /*do the work*/
    return id;

So for example using the above data...

getmestuff(dictlist, 'mp4', 720)

Would return... pies

Upvotes: 1

Views: 8144

Answers (2)

mgilson
mgilson

Reputation: 309919

how about this:

mp4s = (d for d in dictlist if d['ext'] == 'mp4')
max(mp4s, key=lambda x: x['height'])

This will return the "max" dictionary -- From there getting the id is easy. (and you could easily inline the mp4s, but I've broken it into 2 lines for clarity.)

A little less easy to read, but more compact:

max(dictlist, key=lambda d: (d['ext'] == 'mp4', d['height']))

The first version will also helpfully raise a ValueError if there are no mp4's in the list whereas the second version will just return the thing with the biggest height in that case.

Upvotes: 6

Padraic Cunningham
Padraic Cunningham

Reputation: 180401

A function to do the same:

def get_me_stuff(dict_l, val, max_h):
    best = 0
    id = None
    for d in dict_l:
        h = d.get('height')
        if d.get("ext") == val and max_h > h > best:
            best = h
            id = d.get("id")
    return id

Upvotes: 0

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