Dictionary in Python

Dictionary is used to represent a collection of keys and values pair of data.

Syntax

fruitsCollection= {'apple', 'pear', 'orange', 'banana'}

print fruitsCollection

output

set(['orange', 'pear', 'banana', 'apple'])

userCollection = {'1': 'Mac', '2': 'ALEN','3':'Kenneth'}

del userCollection['1']

print userCollection

output

{'3': 'Kenneth', '2': 'ALEN'}

for i, j in userCollection.items():

          print(i,j)

Output

('3', 'Kenneth')

('2', 'ALEN')

Dictionary Manipulation functions

dict1 = { }                               Empty dictionary

dict2 = {'Aa': 2, 'Bb': 3}           Two-item dictionary

dict2['session']                         Indexing by key

dict2.has_key('UserName'),      UserName' in dict2 membership test

dict2.keys( ), dict2.values( ),

dict2.items( )                           lists of keys, values, items

dict2.copy( ),

dict2.update(dict1)                   shallow copy, dict merging

dict2.get(key, default=None)   "indexing"

len(dict1)                                 Length (number stored entries)

dict2[key] = 300                      Adding/changing

del dict2[key]                          deleting

dict = dict(zip(klist, vlist))        Construction