CODEWITHSUNDEEP
pythonlistsortingpython-3.xdictionary
ohid
ohid

Reputation: 914

Sorting list of values in the returned dictionary in ascending order-Python

Following functions return a reverse of the input dictionary where the values of the original dictionary are used as keys for the returned dictionary and the keys of the original dictionary are used as value for the returned dictionary:

def lower(d):
    return dict((k.lower(), [item.lower() for item in v]) for k, v in d.iteritems())

def reverse_dictionary(input_dict):
    D=lower(input_dict)
    reverse_dict = {}
    for key, value in D.iteritems():
        if not isinstance(value, (list, tuple)):
            value = [value]
        for val in value:
            reverse_dict[val] = reverse_dict.get(val, [])
            reverse_dict[val].append(key)
    for key, value in reverse_dict.iteritems():
        if len(value) == 1:
            reverse_dict[key] = value[0]

    return reverse_dict
input_dict= {'astute': ['Smart', 'clever', 'talented'], 
            'Accurate': ['exact', 'precise'], 
            'exact': ['precise'], 'talented': ['smart', 'keen', 'Bright'], 
            'smart': ['clever', 'bright', 'talented']}
print(reverse_dictionary(input_dict))

But list of values in the returned dictionary is not sorted in ascending order.

This function returns:

{'precise': ['accurate', 'exact'], 'clever': ['astute', 'smart'], 'talented': ['astute', 'smart'], 'keen': 'talented', 'bright': ['talented', 'smart'], 'exact': 'accurate', 'smart': ['astute', 'talented']}

The correct output is:

{'precise': ['accurate', 'exact'], 'clever': ['astute', 'smart'], 'talented': ['astute', 'smart'], 'keen': ['talented'], 'bright': ['smart', 'talented'], 'exact': ['accurate'], 'smart': ['astute', 'talented']}

Any help will be much appreciated.

Upvotes: 1

Views: 620

Answers (3)

snakecharmerb
snakecharmerb

Reputation: 55933

If you want the values lists to be sorted, you'll need to do so explicitly.

This should work:

def reverse_dictionary(input_dict):
    D=lower(input_dict)
    reverse_dict = {}
    for key, value in D.iteritems():
        if not isinstance(value, (list, tuple)):
            value = [value]
        for val in value:
            reverse_dict[val] = reverse_dict.get(val, [])
            reverse_dict[val].append(key)
    for key, value in reverse_dict.iteritems():
        if len(value) > 1:
            reverse_dict[key] = sorted(value)

Upvotes: 0

eskaev
eskaev

Reputation: 1128

You can directly iterate over the sorted (key, value) pairs:

for key, value in sorted(D.iteritems()):
    ...

Or sort the values once the reversed dictionary has been constructed:

for key, value in reverse_dict.iteritems():
    value.sort()
    ...

Upvotes: 0

Mureinik
Mureinik

Reputation: 312267

reverse_dict is just a plain old dictionary, that does not retain the order you add elements to it, rendering the entire method somewhat pointless. Instead, if you wish to retain the order of insertion, you should use OrderedDict from the collections module (from collections import OrderedDict) when initializing this variable:

reverse_dict = OrderedDict();

Upvotes: 1

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