Скачать или смотреть How to Extract Your Base Name with str_detect in R

Learn how to efficiently extract the base name from a file path in R using `str_detect` and other methods. Perfect for R beginners and enthusiasts!
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This video is based on the question https://stackoverflow.com/q/71562376/ asked by the user 'juandmaz' ( https://stackoverflow.com/u/17692687/ ) and on the answer https://stackoverflow.com/a/71633209/ provided by the user 'anuanand' ( https://stackoverflow.com/u/9014882/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Extract Your Base Name with str_detect in R

When working with files in R, you might find yourself needing to extract the base name of a file from a full directory path. For instance, if you have the following file path:

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

your goal would be to pull out just the base name, ListData-entry2018, without specifying the file name beforehand. This can be accomplished in several ways, and in this post, we will explore how to effectively do this using str_detect and other related functions.

Understanding the Problem

Before diving into the solution, let’s clarify the requirement:

Input: A full file path, e.g., Data/Bases/Canonical/ListData-entry2018.xls

Output: The base name without the extension, e.g., ListData-entry2018

Solution Approaches

1. Using the tools Package

One straightforward approach is to utilize the tools package that offers built-in functions specifically designed for file manipulation.

Steps:

Get the base name from the path.

Remove the extension using file_path_sans_ext.

Code Example:

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2. Using sub with Regular Expressions

If you’re looking for a more regex-centric approach, you can use the sub function to match and remove the file extension.

Steps:

Use a regex pattern to capture everything before the last dot.

Code Example:

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3. Using substr for Fixed-Length Extensions

Another method is to assume that file extensions are of a fixed character length (usually three). You can then manipulate the string directly using substr.

Steps:

Calculate the length of the base name and exclude the last four characters (three for the extension and one for the dot).

Code Example:

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Summary of Methods

All methods yield the same result, which demonstrates flexibility in approach. Here’s a quick recap of the outputs:

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Conclusion

Extracting the base name from a file path in R can be accomplished through various methods, including the use of built-in functions, regex, and simple string manipulation. Each method has its strengths and can be selected based on your specific needs and coding style.

Feel free to adapt these techniques into your own projects and happy coding!