In this Python Dictionary article we want to talk about Advance Python Dictionary Techniques, so Python dictionaries are one of the most useful data structures in Python. they allows you to store data in key value pairs, and this makes it easy to retrieve and manipulate data in a fast and efficient way. in this article we want to talk about some advance Python dictionary techniques that can help you take your programming skills to the next level.
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Default Dictionaries
One of the most common problems when working with Python dictionaries is when you try to access a key that does not exist in the dictionary. this results in KeyError being raised, which can be inconvenient and time consuming to handle. defaultdict class from the collections module provides a solution to this problem. when you create defaultdict, you specify default factory function that will be called to provide a default value for missing key. this is the example.
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from collections import defaultdict # Creat defaultdict with an int factory function dd = defaultdict(int) # Add some values to the dictionary dd['a'] = 1 dd['b'] = 2 # Access missing key print(dd['c']) |
If you run this code the result will be zero.
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Merging Dictionaries
Python provides an easy way to merge dictionaries using the update method. this method updates the dictionary with key value pairs from another dictionary. this is an example.
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# Create two dictionaries d1 = {'a': 1, 'b': 2} d2 = {'b': 3, 'c': 4} # Merge d2 into d1 d1.update(d2) # Print the result print(d1) |
This will be the result
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Dictionary Comprehension
Like list comprehension, dictionary comprehension is powerful technique for creating dictionaries in easy way. it allows you to create dictionaries in single line of code using simple syntax. this is an example:
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# Create dictionary using dictionary comprehension d = {x: x**2 for x in range(5)} # Print the result print(d) |
This will be the result
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Sorting Dictionaries
By default dictionaries in Python are unordered. however, you can sort a dictionary by its keys or values using the sorted function.
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# Create dictionary d = {'b': 3, 'a': 1, 'c': 4} # Sort dictionary by keys sorted_d_keys = {k: d[k] for k in sorted(d)} # Sort dictionary by values sorted_d_values = {k: v for k, v in sorted(d.items(), key=lambda item: item[1])} # Print results print(sorted_d_keys) print(sorted_d_values) |
This will be the result
