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Learn how to effectively remove characters from specific lines in a string with Python, especially when dealing with .obj files.
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This video is based on the question https://stackoverflow.com/q/66297808/ asked by the user 'Jack Harris' ( https://stackoverflow.com/u/10426622/ ) and on the answer https://stackoverflow.com/a/66297859/ provided by the user 'Willis Blackburn' ( https://stackoverflow.com/u/2684196/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Delete 4 Characters from the End of Certain Lines in a String

Working with text files in programming can be tricky, especially when you need to manipulate individual lines in the string. A common scenario arises when you need to remove a specific number of characters from certain lines based on specific criteria. In this guide, we will tackle the problem of deleting 4 characters from the end of lines that start with the letter 'g' in a text file format known as .obj.

Understanding the Problem

The .obj file format is commonly used in 3D graphics and is structured in a way that includes different identifiers. In our case, we are dealing with lines that start with 'g', which are followed by a name and a number. For instance:

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Our goal is to remove the last four characters, specifically the underscore and the digits, leaving us with just the identifier name (like lCollar or lShldr).

Example Input

Here's a snippet from the .obj file:

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The Proposed Solution

To achieve our goal, we will edit the .obj file by iterating through each line, checking if it starts with 'g', and then removing the last four characters when this condition is met. Let’s break down the solution step by step.

Step 1: Open and Read the File

First, we need to ensure that we can read the contents of the file. We will open the file and read its data:

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Step 2: Process Each Line

Next, we will split the data into lines and iterate over each line. We will check if a line starts with 'g', and if so, we will modify it:

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Step 3: Write to a New File

Since modifying the content doesn't update the original data variable, we need to create a new file to save our changes:

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Summary of the Code

Here’s the complete code that incorporates all the steps mentioned above:

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

Conclusion

By following the steps outlined above, you will be able to successfully remove the last four characters from all lines that start with 'g' in your .obj file. This technique can be particularly useful for file manipulation in game development or other 3D applications.

Feel free to adapt this method to suit different conditions and needs when dealing with strings in Python!