When to use a dictionary in Python | Basics

Use a dictionary data type when the data has a unique reference that can be associated with the value in Python. A dictionary is a mapping, which means the relation between keys and values is not symmetrical. For example, it’s tricky to fetch a key by a known value.

dict – if you require to relate values with keys

Note: dictionaries are mutable, you can’t modify them in the first place.

Example use a dictionary in Python

Simple example code dict associates each key with a value, while list and set just contain values: very different use cases.

employees = {"1": "George", "2": "Nell", "3": "Jasper"}


print(employees)

Output:

Here are some common situations where you might want to use a dictionary in Python:

1. Mapping values: Dictionaries are often used to map one value to another. For example, you can use a dictionary to map the names of students to their corresponding grades in a class.
2. Fast lookup: Dictionaries provide a fast lookup based on keys. If you have a large collection of data and you need to retrieve values based on certain keys, dictionaries offer efficient retrieval by using a hash table.
3. Grouping and aggregation: Dictionaries are useful for grouping and aggregating data. You can use a dictionary to group similar items together and perform operations on them. For example, you can group a list of students by their grades and calculate the average grade for each group.
4. Configuration settings: Dictionaries can be used to store configuration settings for your programs. You can define various parameters and their corresponding values in a dictionary, making it easy to access and modify the settings as needed.
5. Counting occurrences: Dictionaries are handy when you need to count the occurrences of elements in a collection. For instance, you can create a dictionary where the keys are elements from a list, and the values represent the number of times each element appears.
6. Caching and memoization: Dictionaries can be employed for caching and memoization purposes. If you have a function that takes a long time to compute a result, you can store the computed results in a dictionary based on the function’s input parameters. This way, if the function is called again with the same parameters, you can retrieve the result from the dictionary instead of re-computing it.

Overall, dictionaries in Python are versatile and provide a convenient way to store, retrieve, and manipulate data based on key-value pairs. They are particularly useful when you need to perform fast lookups or when you want to organize data in a structured manner.

Comment if you have any doubts or suggestions on this Python basic tutorial.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.