Dictionary Methods and Operations: A Comprehensive Guide | Python Tutorial #4
In Python, a dictionary is a collection of key-value pairs. It is an unordered data structure that stores data in a mapping rather than in a sequence.
Here are a few examples of dictionary operations in Python:
Accessing: You can access the value associated with a key in a dictionary by using the key in square brackets. For example, given the dictionary my_dict = {'a': 1, 'b': 2}, you can access the value 1 with my_dict['a'].
Modification: You can change the value associated with a key in a dictionary by assigning a new value to it. For example, my_dict['a'] = 3 will change the value associated with the key 'a' to 3.
Addition: You can add a new key-value pair to a dictionary by assigning a value to a new key. For example, my_dict['c'] = 4 will add the key-value pair 'c': 4 to the dictionary.
Deletion: You can delete a key-value pair from a dictionary using the del statement. For example, del my_dict['a'] will remove the key-value pair 'a': 1 from the dictionary.
Membership: You can test whether a key is in a dictionary using the in operator. For example, 'a' in my_dict will return True, while 'd' in my_dict will return False.
Iteration: You can iterate over the keys in a dictionary using a for loop. For example, you can use for key in my_dict: to iterate over the keys in my_dict. You can also use the items() method to iterate over the key-value pairs in a dictionary.
Length: You can get the number of key-value pairs in a dictionary using the len() function. For example, len(my_dict) will return 2.