Filter Dict to Contain Only Certain Keys

Filter dict to contain only certain keys?

Constructing a new dict:

dict_you_want = { your_key: old_dict[your_key] for your_key in your_keys }

Uses dictionary comprehension.

If you use a version which lacks them (ie Python 2.6 and earlier), make it dict((your_key, old_dict[your_key]) for ...). It's the same, though uglier.

Note that this, unlike jnnnnn's version, has stable performance (depends only on number of your_keys) for old_dicts of any size. Both in terms of speed and memory. Since this is a generator expression, it processes one item at a time, and it doesn't looks through all items of old_dict.

Removing everything in-place:

unwanted = set(keys) - set(your_dict)
for unwanted_key in unwanted: del your_dict[unwanted_key]

filter items in a python dictionary where keys contain a specific string

How about a dict comprehension:

filtered_dict = {k:v for k,v in d.iteritems() if filter_string in k}

One you see it, it should be self-explanatory, as it reads like English pretty well.

This syntax requires Python 2.7 or greater.

In Python 3, there is only dict.items(), not iteritems() so you would use:

filtered_dict = {k:v for (k,v) in d.items() if filter_string in k}

Filter a dictionary to return certain keys

You can create a dictionary with needed keys and their respective values via dictionary comprehension and add it to new_list

#List of keys you need
needed_keys = ['trip_distance', 'pickup_latitude', 'pickup_longitude']

#Iterate over trips list
for trip in trips:

    #Create a dictionary with needed keys and their respective values and add it to result
    new_list.append({k:trip[k] for k in needed_keys})

How to to filter dict to select only keys greater than a value?

[v for k,v in mydict.items() if k >= 6]

Filter Json Keys that contains certain character in Python

This can be accomplished with a dict comprehension, which can be updated based on your needed filter:

new_dict = {key: value for key, value in info['store'].items() if "book" in key}

Filter dictionary based on list of keys

Simply:

d2 = {k:d[k] for k in lst}

But all keys must exist in the source directory. If not:

d2 = {k:d[k] for k in lst if k in d}

Python: How to select and then compare and filter certain values in a dict?

You don't need the sorted list of keys.

result = sorted(newdict.items(), key=lambda x: x[1], reverse=True)[:3]

This returns a list of (key, value) tuples.

Python filter nested Dict

Since you have a nested dictionary, your filtering logic also has to be nested. Here's an example that works with the sample data you've provided and returns the filtered data in its original structure:

new_dict = {
    "clients": [{
        "name": client["name"],
        "data": {
            "gender": client["data"]["gender"],
            "telephones": [
                phone
                for phone in client["data"].get("telephones", [])
                if "home" in phone
            ]
        }
    } for client in client_dict["clients"]]
}

If you wanted to do it without hardcoding the specific structure, a recursive function is a good way to handle arbitrary nesting. Here's an example with a function that takes a set of keys to include; this produces a slightly nicer result than the hard-coded version because it can filter out the empty telephones list if there's no home phone given:

def filter_nested_dict(obj, keys):
    if isinstance(obj, list):
        new_list = []
        for i in obj:
            new_i = filter_nested_dict(i, keys)
            if new_i:
                new_list.append(new_i)
        return new_list
    if isinstance(obj, dict):
        new_dict = {}
        for k, v in obj.items():
            if k not in keys:
                continue
            new_v = filter_nested_dict(v, keys)
            if new_v:
                new_dict[k] = new_v
        return new_dict
    return obj

new_dict = filter_nested_dict(
    client_dict,
    {"clients", "name", "data", "gender", "telephones", "home"}
)

from pprint import pprint
pprint(new_dict)

Result:

{'clients': [{'data': {'gender': 'Male'}, 'name': 'John A'},
             {'data': {'gender': 'Male',
                       'telephones': [{'home': '1234567890'}]},
              'name': 'John B'}]}

---

Related Topics