dictionary values in python adding values

Question

So here is my problem, i have a dictionary with following key => values:

6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:политичка -> 2
6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:државата -> 2
6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:енергично -> 1
1caa60ebf9459d9cd406f1a03e1719b675dcfaad78292edc7e4a56be:полициска -> 1

I have this code to show the keys needed:

for key, value in count_db.iteritems():
        print key[:56]

So now i have:

6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002 -> 2
6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002 -> 2
6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002 -> 1
1caa60ebf9459d9cd406f1a03e1719b675dcfaad78292edc7e4a56be -> 1

I need to merge them into:

6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002 -> 5
1caa60ebf9459d9cd406f1a03e1719b675dcfaad78292edc7e4a56be -> 1

I have made this but i have not succeed in doing it correctly:

length_dic=len(count_db.keys())
for key, value in count_db.iteritems():
    count_element=key[:56]
    #print "%s => %s" % (key[:56], value) #value[:56]

    for i in range(length_dic):
        i+=1
        if count_element == key[:56]:
            itr+=int(value) 
        print i
    length_dic=length_dic-1

Any hints?

mensi · Accepted Answer · 2012-04-11 12:13:40Z

4

A trivial approach would be:

result = {}
for key, value in count_db.iteritems():
    result[key[:56]] = result.get(key[:56], 0) + value

You could also achieve the same with reduce if you want to get it on one line:

import collections
result = reduce(lambda x,y: x[y[0][:56]] += y[1] , count_db.iteritems(), collections.defaultdict(int))

edited Apr 11, 2012 at 12:13

answered Apr 11, 2012 at 12:05

mensi

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2 Comments

mensi Over a year ago

@DameJovanoski Every time you need to do some conversion or transformation on a dict or a list, there is usually a one-line solution, even though it might not look pretty ;)

badc0re Over a year ago

When i try to print the list i get ValueError: too many values to unpack Any hints?

Abhijit · Accepted Answer · 2012-04-11 12:09:47Z

1

Given your dictionary as

>>> spam={"6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:AAAA": 2,
"6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:BBBB": 2,
"6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002:CCCC": 1,
"1caa60ebf9459d9cd406f1a03e1719b675dcfaad78292edc7e4a56be:DDDD": 1
}

you can somewhat do like the following

>>> bacon=collections.defaultdict(int)
>>> for k,v in [(k[:56],v) for k,v in spam.iteritems()]:
    bacon[k]+=v


>>> bacon
defaultdict(<type 'int'>, {'6bc51fb21fd9eefef4ec97a241733cd59b71e8e14ad70e9068d32002': 5, '1caa60ebf9459d9cd406f1a03e1719b675dcfaad78292edc7e4a56be': 1})
>>>

answered Apr 11, 2012 at 12:09

Abhijit

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Comments

Tim Lesher · Accepted Answer · 2012-04-11 17:48:57Z

0

This is exactly what the Counter object (in version 2.7+) is for:

import collections
c = collections.Counter()

for key, value in count_db.iteritems():
    c[key[:56]] += value

answered Apr 11, 2012 at 17:48

Tim Lesher

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1 Comment

badc0re Over a year ago

ValueError: too many values to unpack when i want to print it

jadkik94 · Accepted Answer · 2012-04-11 12:11:57Z

0

I didn't understand why you did all that in your code. I think this would do the job:

tmp_dict = {}
for key, value in count_db.iteritems():
    count_element=key[:56]

    if count_element in tmp_dict:
        tmp_dict[count_element] += value
    else:
        tmp_dict[count_element] = value

answered Apr 11, 2012 at 12:11

jadkik94

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