How to Convert a Comma Separated String into a List of Points in Python

Learn how to effectively separate a `comma separated string` and convert it into a list of Points using Python.
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This video is based on the question https://stackoverflow.com/q/68541001/ asked by the user 'Shadow Walker' ( https://stackoverflow.com/u/10617728/ ) and on the answer https://stackoverflow.com/a/68541050/ provided by the user 'Sayse' ( https://stackoverflow.com/u/1324033/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Convert a Comma Separated String into a List of Points in Python

Dealing with data input in the form of strings is a common task in programming. If you're working with a string of coordinates formatted with commas and parentheses, you might find yourself needing to convert that string into a more usable format, such as a list of Point objects in Python. In this guide, we will discuss how to effectively achieve this and resolve the issue presented in the question.

The Problem

You have a comma separated string that looks like this:

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The goal is to convert this string into a list of Point objects. The example output you desire looks like this:

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However, the initial code does not work because the split() method is being used incorrectly. Let's break down the solution step-by-step.

Understanding the Original Code's Issue

In the provided code, this line is used:

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

The split() method, when called without any arguments, breaks the string at whitespace. Therefore, if you use it on your string s, you'll get a list that still contains string representations of the coordinates but not in the format you need.

Incorrect Output

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This output won't help you create the list of Point objects directly.

The Solution

Instead of trying to split the string improperly, one effective way to convert the string into Points is to evaluate it as a tuple using Python's built-in ast.literal_eval. Here's how you can do it:

Step-by-Step Instructions

Import the Necessary Module: First, you need to import the literal_eval function from the ast module. This function safely evaluates a string containing a Python literal or container.

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Use literal_eval to Convert the String: This will allow you to convert the string to an actual tuple of coordinates that Python can understand.

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Construct the List of Points: Finally, use list comprehension to create the list of Point objects from the evaluated coordinates.

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Example Code

Here’s the complete code that implements the above instructions:

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

Conclusion

By using literal_eval, you can avoid the pitfalls of incorrect string manipulation and directly convert a well-formatted string of coordinates into a list of Point objects in Python. This method is clean, efficient, and leverages Python’s capability to safely evaluate strings resembling Python expressions.

Now that you know how to effectively separate a comma-separated string into useful data types, you can manage similar tasks more efficiently in your coding projects.