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Learn how to efficiently search for a value in a column of lists in a pandas DataFrame and retrieve the corresponding value from another column.
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How to Find a Value in a Column of Lists in a Pandas DataFrame

When working with data in Python, particularly using the pandas library, you may encounter situations where one of your DataFrame columns consists of lists. This can make searching through the data a bit challenging. In this guide, we will address a common problem: how to find a value in a column of lists and retrieve a corresponding value from another column.

The Problem

Imagine you have a DataFrame with two columns: A and B. Column A contains string values (categories), and column B consists of lists of strings (zones). Here’s an example of what your DataFrame might look like:

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

Suppose you want to find out which category corresponds to zone zn_1. In this case, you need to search through column B and get the matching category from column A.

The Solution

Let’s break down the steps to achieve this in an organized manner.

Step 1: Set Up Your DataFrame

First, make sure you have pandas installed. If not, you can install it using pip:

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

Then, create your DataFrame:

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

Step 2: Use str.contains to Search

You can utilize the str.contains method in pandas to search for your desired zone within the lists in column B. Here's how to do that:

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

Step 3: Retrieve the Result

The above code will return a Series containing the categories that match the condition. If you only need the first match as a string instead of a Series, you can convert it as follows:

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

Summary of the Code

Here’s the full code snippet that combines everything:

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

Conclusion

Searching for a value in a column of lists in a pandas DataFrame may seem complex at first, but with the use of the str.contains method, it becomes a straightforward task. By following the steps outlined above, you can efficiently retrieve the corresponding category for any given zone.

If you have more questions about using pandas or data manipulation in Python, feel free to ask!