Скачать или смотреть Sorting a Pandas DataFrame by Specified Column Order

Learn how to efficiently sort a Pandas DataFrame by a specific column using an ordered list of values. This comprehensive guide will walk you through two effective approaches with code examples.
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Sorting a Pandas DataFrame by Specified Column Order: A Step-by-Step Guide

When working with Pandas DataFrames, you might come across a situation where you need to sort a DataFrame based on a specific column using a predefined order. This problem often arises when dealing with categorical data where the values have a logical sequence. In this post, we will explore how to sort a Pandas DataFrame using an ordered list for a specified column.

The Problem

Imagine you have a DataFrame containing various fruits along with their respective id and trash values, and you want to sort this DataFrame based on the column fruit, according to a custom order provided in a list. For instance, consider the following DataFrame:

[[See Video to Reveal this Text or Code Snippet]]

You have an ordered list as follows:

[[See Video to Reveal this Text or Code Snippet]]

Given this data, you want to sort your DataFrame to achieve the desired output, which looks like this:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

We will explore two efficient approaches to achieve this sorting in Pandas: using Ordered Categorical and a key function.

Approach 1: Using Ordered Categorical

One straightforward method to sort the DataFrame is by converting the fruit column into an ordered categorical type. Here’s how to do it:

Convert the fruit column to a categorical type using the ordered list.

Sort the DataFrame based on the fruit column.

Here’s the code implementing this approach:

[[See Video to Reveal this Text or Code Snippet]]

Approach 2: Using a Key Function

Another efficient way to sort the DataFrame is by using the sort_values method with a key function. This method maps the fruit names to their corresponding order based on their index in the ordered list:

[[See Video to Reveal this Text or Code Snippet]]

Final Output

Regardless of the approach chosen, the final sorted DataFrame will look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

In conclusion, sorting a Pandas DataFrame by a specified column using a pre-defined order can be efficiently achieved through two different methods: transforming the column to a categorical type or utilizing a sorting key function. Both methods are effective and should serve well, especially when handling larger DataFrames with multiple unique values.

Now you can easily sort your DataFrame based on any categorical variable with a clear order, making your data analysis tasks more intuitive and efficient!