Dictionary

Dictionary is an unordered set of key-value pairs where the keys are unique. Dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys. Tuples can be used as keys if they contain only strings, numbers, or tuples.



In [3]:

    
dict1 = {'id': 1, 'name':'John Doe', 'email':'john.doe@example.org','salary':14000.00}
dict1









    Out[3]:





{'email': 'john.doe@example.org',
 'id': 1,
 'name': 'John Doe',
 'salary': 14000.0}



In [4]:

    
dict1['name']









    Out[4]:





'John Doe'



In [5]:

    
dict1['email']='john.doe@example.com'



In [6]:

    
dict1









    Out[6]:





{'email': 'john.doe@example.com',
 'id': 1,
 'name': 'John Doe',
 'salary': 14000.0}



In [24]:

    
type(dict1)









    Out[24]:





dict



In [25]:

    
str(dict1)









    Out[25]:





"{'id': 1, 'name': 'John Doe', 'email': 'john.doe@example.com', 'salary': 14000.0}"



In [7]:

    
list(dict1.keys())









    Out[7]:





['id', 'name', 'email', 'salary']



In [8]:

    
list(dict1.values())









    Out[8]:





[1, 'John Doe', 'john.doe@example.com', 14000.0]



In [9]:

    
sorted(list(dict1.keys()))









    Out[9]:





['email', 'id', 'name', 'salary']



In [43]:

    
del(list)









    



---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-43-0fc84f4d1c3e> in <module>()
----> 1 del(list)

NameError: name 'list' is not defined



In [14]:

    
dict2 = dict([('id',2),('name','Jack Jill'),('salary',15500)])
dict2









    Out[14]:





{'id': 2, 'name': 'Jack Jill', 'salary': 15500}



In [23]:

    
dict(id=3, salary=25000)









    



---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-23-e0bf2f8c9570> in <module>()
----> 1 dict(id=3, salary=25000)

TypeError: 'list' object is not callable



In [16]:

    
dict = [dict1,dict2]
dict









    Out[16]:





[{'email': 'john.doe@example.com',
  'id': 1,
  'name': 'John Doe',
  'salary': 14000.0},
 {'id': 2, 'name': 'Jack Jill', 'salary': 15500}]



In [17]:

    
dict[1]['name']









    Out[17]:





'Jack Jill'

Dictionary Comprehension



In [18]:

    
{x: x**2 for x in range(10) if x%2 == 0}









    Out[18]:





{0: 0, 2: 4, 4: 16, 6: 36, 8: 64}

Looping Techniques



In [29]:

    
people = {'name':'John','email':'john@example.com'}
for k,v in people.items():
    print(k, v)









    



name John
email john@example.com



In [31]:

    
for key in people:
    print(people[key])









    



John
john@example.com



In [32]:

    
for value in people.values():
    print(value)









    



John
john@example.com



In [33]:

    
for key in people.keys():
    print(key)









    



name
email



In [47]:

    
__builtins__.list
countries = ["USA","England","France","India","Japan"]
capitals = ["Washington","London","Paris","New Delhi","Tokyo"]
countries_dict = dict(zip(countries,capitals))
print(countries_dict)









    



---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-47-e72d4a649579> in <module>()
      2 countries = ["USA","England","France","India","Japan"]
      3 capitals = ["Washington","London","Paris","New Delhi","Tokyo"]
----> 4 countries_dict = dict(zip(countries,capitals))
      5 print(countries_dict)

TypeError: 'list' object is not callable



In [ ]: