Python Dictionary Object Example

Let's learn how to work with python dictionary, dictionary is a collection object, here we see examples of how to create a python dictionary object, how python dictionary works, what are the built-in methods in dictionary object, and what type of data we can store in a dictionary object.

Dict = {'Course' : 'Python', 10: [14,4.5,.60], 'Provider' : 'WebTrainingRoom'} 

Python Dictionary is a collection type object, which can store data using keay value “key:value” pair, in this article we will learn how to work with Python dictionary object.

We can create python dictionary object different ways, here are few examples.

    
class DictionaryExample(object):
    def __init__(self):
         self.Title = "Dictionary Examples";
    def showFunction(obj):
        Dict = {"Course:Python"} 
        print("New Dictionary created") 
        print(Dict) 

Python dictionary functions tutorial

We can create dictionary object with different type of keys, but we must make sure providing right key at the time of retrieval

Dict = {'Course' : 'Python', 10: [14,4.5,.60], 'Provider' : 'WebTrainingRoom'} 
print(Dict)

We also can create dictionary with dict() method.

Dict = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
print(Dict) 

Here are some python dictionary methods with examples.

1. Removes all the elements from the dictionary, make it empty. clear()

   Dict = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   Dict.clear(); 
   print(Dict) 
   

2. Copy a dictionary object with data to a new dictionary object. copy()

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   d2=d1.copy(); 
   print(d2) 
   

3. Get all keys of a dictionary object, useful when you want to retrieve value by using a key. keys()

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   allkeys=d1.keys(); 
   

4. popitem() : Pick the last item from the dictionary

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   d2=d1.popitem(); 
   print(d2);
   #result : (3, 'Blue')
   

5. Pick the Specified item based on given key from the dictionary, if no matching key found then it throws error. pop()

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   d2=d1.pop(2); 
   print(d2);
   #result : ('Green')
   

6. Insert an item to the dictionary object; update python dictionary with new item. update()

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   d1.update({"color": "Orange"}); 
   print(d1) 
   #result : {1: 'Red', 2: 'Green', 3:'Blue', "color": "Orange"} 
   

7. Get all values of a dictionary object, useful when you want to retrieve all values. values()

   d1 = dict({1: 'Red', 2: 'Green', 3:'Blue'}) 
   allValues=d1.values(); 
   

8. There is no direct method for sorting a dictionary collection in python, but we can make a list object of all keys in dictionary, then we can sort the key-list, here is an example of how to sort a dictionary object in python. sort()

   Dict  = dict({"India": 'Delhi', "Uk": 'London', "USA":'Washington'})         
   lst1=list(Dict.keys());
   lst1.sort();
   for K in lst1:
       print(":".join((K,str(Dict[K]))));
   

9. this method is to find the length of a dictionary collection in python. len()

   Dict  = dict({"India": 'Delhi', "Uk": 'London', "USA":'Washington'}) 
   print("Length : %d" % len (Dict))
   

10. this will form a string from given dictionary object. str()

    Dict  = dict({"India": 'Delhi', "Uk": 'London', "USA":'Washington'})
    print(str(Dict))
    

After using dictionary object, we can finally delete the dictionary using "del" key word.

country =	{
  "name": "India",
  "game": "Cricket",
  "river": "Ganga"
}
del country

Python dictionary is just like generic list object that allow us to store values with key, we can add , remove any number of items, we can retrieve item by using key.