Python Dictionary

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Dictionary overview

Dictionaries are used to store data values in key:value pairs. A dictionary is a collection which is ordered*, changeable and do not allow duplicates. Dictionaries are written with curly brackets, and have keys and values:
				
					dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
print(dict['Name'])
#print (dict['Age12'])
#print(dict)
				
			

Accessing Items

You can access the items of a dictionary by referring to its key name, inside square brackets:

There is also a method called get() that will give you the same result:

				
					dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
print(dict['Name'])
print(dict.get("Name))
				
			

Dictionary Update Items

Using Below Code snippts shows the Updating Items in dicitionary.

				
					dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
dict['Age'] = 8 # we are adding the key and value pair
				
			

Dictionary Remove item

The del keyword removes the item with the specified key name:

				
					test_dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
del test_dict['Name']; # remove entry with key 'Name'
del test_dict ;        # delete entire dictionary
				
			

Loop Dictionaries

Loop through both keys and values, by using the items() method:

				
					test_dict = {1:'aakash',2:'kumar',3:'Bihar',4:'piro'}
#print(test_dict.items())
#print(test_dict.items())
for k, v in test_dict.items():
  print(k," ",v)
				
			

Dictionary keys()

Returns a list containing the dictionary’s keys
				
					ex = {'Name': 'Zara', 'Age': 7}
print(list(ex.keys()))
				
			

Dictionary values()

Returns a list of all the values in the dictionary

				
					ex = {'Name': 'Zara', 'Age': 7}
print(list(ex.values()))
				
			

Dictinoary __contains__()

The __contains__() is used to check whether a key exists , if exists it will give true else False

				
					dict = {'Name': 'Zara', 'Age': 7}
print (dict.__contains__('Name'))  # __contains__('key')
print (dict.__contains__('Sex'))
				
			

Dictionary len()

len() is use to count the number of key and value pair.

				
					ex = {'Name': 'Zara', 'Age': 7,'Class':'Second'}
print(len(ex))
				
			

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