{"id":867,"date":"2024-09-05T09:42:51","date_gmt":"2024-09-05T04:12:51","guid":{"rendered":"https:\/\/www.mrcoder701.com\/?p=867"},"modified":"2024-09-05T20:31:19","modified_gmt":"2024-09-05T15:01:19","slug":"python-dictionaries","status":"publish","type":"post","link":"https:\/\/www.mrcoder701.com\/2024\/09\/05\/python-dictionaries\/","title":{"rendered":"Python Dictionaries"},"content":{"rendered":"

In Python, dictionaries are mutable data structures that allow you to store key-value pairs<\/strong>. The dictionary can be created using the dict() constructor or curly braces’ {}’. Once you have created a dictionary, you can add, remove, or update elements using the methods dict. update(), dict. pop(), and dict.<\/p>

What is a Dictionary in Python?<\/h2>

Imagine a real dictionary (the kind with pages, not the web kind). It’s a collection of words, each with its definition. In Python, a dictionary works similarly. It’s a collection of key-value pairs where each key is unique, and each key maps to a value. This structure makes dictionaries incredibly powerful for organizing and accessing data quickly.<\/p>

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# Creating a simple dictionary<\/span><\/span>\nmy_dict <\/span>=<\/span> {<\/span><\/span>\n    <\/span>"<\/span>name<\/span>"<\/span>: <\/span>"<\/span>Alice<\/span>"<\/span>,<\/span><\/span>\n    <\/span>"<\/span>age<\/span>"<\/span>: <\/span>30<\/span>,<\/span><\/span>\n    <\/span>"<\/span>city<\/span>"<\/span>: <\/span>"<\/span>Wonderland<\/span>"<\/span><\/span>\n}<\/span><\/span>\nprint<\/span>(my_dict)<\/span><\/span>\n<\/span>\n#OutPut<\/span><\/span>\n{<\/span>'<\/span>name<\/span>'<\/span>: <\/span>'<\/span>Alice<\/span>'<\/span>, <\/span>'<\/span>age<\/span>'<\/span>: <\/span>30<\/span>, <\/span>'<\/span>city<\/span>'<\/span>: <\/span>'<\/span>Wonderland<\/span>'<\/span>}<\/span><\/span>\n<\/span><\/code><\/pre><\/div>
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Creating and Initializing Dictionaries<\/h2>
There are several ways to create and initialize dictionaries in Python. Let’s explore these methods.<\/p>
Empty Dictionary<\/h4>
You can create an empty dictionary using curly braces {}<\/code> or the dict()<\/code> constructor.<\/p>
Example:<\/strong><\/p>
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# Using curly braces<\/span><\/span>\nempty_dict <\/span>=<\/span> {}<\/span><\/span>\nprint<\/span>(empty_dict)  <\/span># Output: {}<\/span><\/span>\n<\/span>\n# Using the dict() constructor<\/span><\/span>\nempty_dict2 <\/span>=<\/span> <\/span>dict<\/span>()<\/span><\/span>\nprint<\/span>(empty_dict2)  <\/span># Output: {}<\/span><\/span><\/code><\/pre><\/div>
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Initializing with Key-Value Pairs<\/h4>
You can initialize a dictionary directly with key-value pairs.<\/p>
Example:<\/strong><\/p>
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# Direct initialization<\/span><\/span>\nperson <\/span>=<\/span> {<\/span><\/span>\n    <\/span>"<\/span>name<\/span>"<\/span>: <\/span>"<\/span>Alice<\/span>"<\/span>,<\/span><\/span>\n    <\/span>"<\/span>age<\/span>"<\/span>: <\/span>30<\/span>,<\/span><\/span>\n    <\/span>"<\/span>city<\/span>"<\/span>: <\/span>"<\/span>Wonderland<\/span>"<\/span><\/span>\n}<\/span><\/span>\nprint<\/span>(person)<\/span><\/span>\n<\/span>\n#output: {'name': 'Alice', 'age': 30, 'city': 'Wonderland'}<\/span><\/span><\/code><\/pre><\/div>
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Using the dict()<\/code> Constructor<\/h4>
The dict()<\/code> constructor can also initialize dictionaries using keyword arguments.<\/p>
Example:<\/strong><\/p>
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# Using dict() with keyword arguments<\/span><\/span>\nperson <\/span>=<\/span> <\/span>dict<\/span>(<\/span>name<\/span>=<\/span>"<\/span>Alice<\/span>"<\/span>, <\/span>age<\/span>=<\/span>30<\/span>, <\/span>city<\/span>=<\/span>"<\/span>Wonderland<\/span>"<\/span>)<\/span><\/span>\nprint<\/span>(person)<\/span><\/span>\n<\/span>\n#output: {'name': 'Alice', 'age': 30, 'city': 'Wonderland'}<\/span><\/span><\/code><\/pre><\/div>
<\/p>
Creating Dictionaries from Sequences<\/h4>
You can create dictionaries from sequences of key-value pairs using the dict()<\/code> constructor.<\/p>
Example:<\/strong><\/p>
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# From a list of tuples<\/span><\/span>\npairs <\/span>=<\/span> [(<\/span>"<\/span>name<\/span>"<\/span>, <\/span>"<\/span>Alice<\/span>"<\/span>), (<\/span>"<\/span>age<\/span>"<\/span>, <\/span>30<\/span>), (<\/span>"<\/span>city<\/span>"<\/span>, <\/span>"<\/span>Wonderland<\/span>"<\/span>)]<\/span><\/span>\nperson <\/span>=<\/span> <\/span>dict<\/span>(pairs)<\/span><\/span>\nprint<\/span>(person)<\/span><\/span>\n<\/span>\n#output: {'name': 'Alice', 'age': 30, 'city': 'Wonderland'}<\/span><\/span><\/code><\/pre><\/div>
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Dictionary Operations<\/h2>
Once you have a dictionary, you can perform various operations to access, add, update, or remove data.<\/p>
Accessing Values<\/h4>
You can access values in a dictionary using the keys.<\/p>
Example:<\/strong><\/p>
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person <\/span>=<\/span> {<\/span>"<\/span>name<\/span>"<\/span>: <\/span>"<\/span>Alice<\/span>"<\/span>, <\/span>"<\/span>age<\/span>"<\/span>: <\/span>30<\/span>, <\/span>"<\/span>city<\/span>"<\/span>: <\/span>"<\/span>Wonderland<\/span>"<\/span>}<\/span><\/span>\nprint<\/span>(person[<\/span>"<\/span>name<\/span>"<\/span>])  <\/span># Output: Alice<\/span><\/span><\/code><\/pre><\/div>
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Adding and Updating Key-Value Pairs<\/h4>
You can add new key-value pairs or update existing ones using the assignment operator.<\/p>
Example:<\/strong><\/p>
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person <\/span>=<\/span> {<\/span>"<\/span>name<\/span>"<\/span>: <\/span>"<\/span>Alice<\/span>"<\/span>, <\/span>"<\/span>age<\/span>"<\/span>: <\/span>30<\/span>, <\/span>"<\/span>city<\/span>"<\/span>: <\/span>"<\/span>Wonderland<\/span>"<\/span>}<\/span><\/span>\nperson[<\/span>"<\/span>email<\/span>"<\/span>] <\/span>=<\/span> <\/span>"<\/span>alice@example.com<\/span>"<\/span>  <\/span># Adding a new key-value pair<\/span><\/span>\nperson[<\/span>"<\/span>age<\/span>"<\/span>] <\/span>=<\/span> <\/span>31<\/span>  <\/span># Updating an existing key-value pair<\/span><\/span>\n<\/span>\nprint<\/span>(person)<\/span><\/span>\n#output: {'name': 'Alice', 'age': 31, 'city': 'Wonderland', 'email': 'alice@example.com'}<\/span><\/span>\n<\/span><\/code><\/pre><\/div>
<\/p>
Removing Key-Value Pairs<\/h4>
You can remove key-value pairs using several methods.<\/p>