Remove duplicate value from dictionary without removing key

问题

I'm new to Python and am having to learn by trial and error, but I haven't been able to find a solution to the problem I'm having.

I have a dictionary that looks something like this:

myDict = {'key1': ['item1', 'item2', 'item3'], 'key2': ['item4', 'item5', 'item6'],  
'key3': 'item7', 'key4': 'item8', 'key5': ['item1', 'item2', 'item3'], 'key6': 'item7'}

I need to remove duplicate values from the dictionary and replace them with an empty value (""). Found a couple solution on here but they are working as intended

for key, value in myDict.items():
    if values not in key newDict.values():
        myDict[key] = value
    else:
        myDict[key] = ""
print newDict

This is removing all the values and is outputting

# newDict:{key1: '', key2: '', key3: '', key4: '', key5: '', key6: '')

I'm looking for the output to be

# newDict = {'key1': '', 'key2':['item4', 'item5', 'item6'], 'key3': '', 'key4':  
'item8', key5: ['item1', 'item2', 'item3'], 'key6': 'item7'}

回答1:

You have the right overall idea, but there are three problems with your code:

You're storing values back into myDict instead of into newDict.
On line 2, you're checking values instead of value.
Also on line 2, key shouldn't be there, and throws a SyntaxError.

Here is the correct code:

newDict = {}
for key, value in myDict.iteritems():
    if value not in newDict.values():
        newDict[key] = value
    else:
        newDict[key] = ""
print newDict

If you're not in the anti-ternary operator camp, you could also shorten it to this:

newDict = {}
for key, value in myDict.iteritems():
    newDict[key] = value if value not in newDict.values() else ""
print newDict

Or, if you would rather just remove the values from the original dict (myDict) instead of building a new one (newDict), you could do this:

foundValues = []
for key, value in myDict.iteritems():
    if value not in foundValues:
        foundValues.append(myDict[key])
    else:
        myDict[key] = ""
print myDict

If you need duplicate values removed in a specific order, check out OrderedDicts.

Update:

In light of the updated requirements -- that values be removed from the original dict, starting from the beginning -- if you're able to simply initialize myDict with an OrderedDict instead of a dict, all you need to do is replace this:

myDict = {'key1': ['item1', 'item2', 'item3'], 'key2': ['item4', 'item5', 'item6'], 'key3': 'item7', 'key4': 'item8', 'key5': ['item1', 'item2', 'item3'], 'key6': 'item7'}

with this:

from collections import OrderedDict

…

myDict = OrderedDict([('key1', ['item1', 'item2', 'item3']), ('key2', ['item4', 'item5', 'item6']), ('key3', 'item7'), ('key4', 'item8'), ('key5', ['item1', 'item2', 'item3']), ('key6', 'item7')])

and then use the same code provided above.

回答2:

This does it:

myDict_values = myDict.values() # better than calling this numerous times
for key in myDict.keys():
    if myDict_values.count(myDict[key]) > 1: myDict[key] = ""

This won't guarantee that key5 will be blank instead of key1, because dictionaries are not ordered.

来源：https://stackoverflow.com/questions/18255068/remove-duplicate-value-from-dictionary-without-removing-key

标签

python

dictionary

duplicates