Answers for "dictionary multiple values per key"

how to have multiple values to a key in dict in python

from collections import defaultdict
 data = [(2010, 2), (2009, 4), (1989, 8), (2009, 7)]
 d = defaultdict(list)
print (d) # output --> defaultdict(<type 'list'>, {})
 for year, month in data:
     d[year].append(month) 
print (d) # output --> defaultdict(<type 'list'>, {2009: [4, 7], 2010: [2], 1989: [8]})

dictionary multiple values per key

key = "somekey"
a.setdefault(key, [])
a[key].append(1)

multiple values in a dictionary python

a["abc"] = [1, 2, "bob"]

how to use multiple keys for single value in dictionary python

#Python Dictionary only contain one key : one value pair.
#You can surely have multiple keys having same value
#Example :-
  dict = {'a':'value1', 'b':'value2', 'c':'value 3'}
#In above we have a and b key having same values