CODEWITHSUNDEEP
python
chaitra
chaitra

Reputation: 45

how to sort a python dictionary having month names as keys

I have a python dictionary like

{'JUL':15,'MAR': 54,'DEC':65,'OCT':90}

I want it to be sorted according to months say, MAR, JUL, OCT and DEC in python.

How can I do it?

Upvotes: 3

Views: 4812

Answers (4)

MSeifert
MSeifert

Reputation: 152587

You want to sort them by the number of the month so you need to create a Mapping from your month abbreviations to the number of that month:

dic = {'JUL':15, 'MAR': 54,'DEC':65,'OCT':90}

import calendar
month_numeric_mapping = {abb: index for abb in dic 
                                    for index, long in enumerate(calendar.month_name[1:]) 
                                    if str.lower(abb) in str.lower(long)}

>>> month_numeric_mapping
{'DEC': 11, 'JUL': 6, 'MAR': 2, 'OCT': 9}

Then you define a function that can be used with sorted to get that number:

def getMonthNumber(item):
    return month_numeric_mapping[item[0]]

and finally you need to have a order-aware dictionary OrderedDict to store the sorted output:

>>> from collections import OrderedDict
>>> a = OrderedDict(sorted(dic.items(), key=getMonthNumber))
>>> a
OrderedDict([('MAR', 54), ('JUL', 15), ('OCT', 90), ('DEC', 65)])

Another possibility is to use calendar.month_abbr:

month_numeric_mapping = {abbr.upper(): i for i, abbr in enumerate(calendar.month_abbr[1:])}

def getMonthNumber(item):
    return month_numeric_mapping[item[0]]

a = OrderedDict(sorted(dic.items(), key=getMonthNumber))
>>> a
OrderedDict([('MAR', 54), ('JUL', 15), ('OCT', 90), ('DEC', 65)])

Upvotes: 4

DhruvPathak
DhruvPathak

Reputation: 43235

Dictionaries are orderless, you cannot sort a dictionary. You would need an ordereddict, which you can create from a list of sorted tuples of key,value pairs of your current dict.

>>> months = ['JAN','FEB','MAR','APR','MAY','JUN','JUL','AUG','SEP','OCT','NOV','DEC']
>>> input = {'JUL':15,'MAR': 54,'DEC':65,'OCT':90}
>>> from collections import OrderedDict
>>> OrderedDict(sorted(input.items(),key =lambda x:months.index(x[0])))
OrderedDict([('MAR', 54), ('JUL', 15), ('OCT', 90), ('DEC', 65)])

Upvotes: 7

João Pedro
João Pedro

Reputation: 546

A key sort function like the PHP ksort():

def ksort(d, func = None):
    keys = d.keys()
    keys.sort(func)
    return keys

for k in ksort(dic):
    print k, d[k]

Upvotes: -1

Hassan Mehmood
Hassan Mehmood

Reputation: 1402

You can use Ordered Dictionaries in Python using collections module. See the below example. 

import collections

print 'Regular dictionary:'
d = {}
d['a'] = 'A'
d['b'] = 'B'
d['c'] = 'C'
d['d'] = 'D'
d['e'] = 'E'

for k, v in d.items():
    print k, v

print '\nOrderedDict:'
d = collections.OrderedDict()
d['a'] = 'A'
d['b'] = 'B'
d['c'] = 'C'
d['d'] = 'D'
d['e'] = 'E'

for k, v in d.items():
    print k, v

Output

Regular dictionary:
a A
c C
b B
e E
d D

OrderedDict:
a A
b B
c C
d D
e E

Upvotes: 0

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