Скачать или смотреть How to Read and Rewrite CSV Files in PowerShell Retaining Only the First X Columns

Learn how to efficiently handle CSV files in PowerShell by reading and rewriting while filtering out unnecessary columns.
---
This video is based on the question https://stackoverflow.com/q/77838792/ asked by the user 'Harry Leboeuf' ( https://stackoverflow.com/u/7568316/ ) and on the answer https://stackoverflow.com/a/77840413/ provided by the user 'Theo' ( https://stackoverflow.com/u/9898643/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Powershell read csv and rewrite with only x first columns

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Efficiently Read and Rewrite CSV Files in PowerShell

CSV (Comma Separated Values) files are a common format for exchanging data, especially in business operations. However, sometimes these files can contain unnecessary commas or empty columns that can clutter the data. In this guide, we’ll discuss how to use PowerShell to read a CSV file and rewrite it, keeping only a specified number of columns.

Understanding the Problem

You may find yourself in a situation where your CSV files include additional, unwanted comma signs or empty columns, making the data cumbersome to process. For instance, consider a CSV that looks like this:

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

Notice how one of the headers is blank, which can hinder data manipulation. Let's dive into how to handle this issue using PowerShell.

Solution Strategy

The following steps outline how to read a CSV file, check for the number of valid columns, and write back to a new CSV file with only the needed information.

Step 1: Import the CSV File

PowerShell allows you to import CSV data easily using the Import-Csv cmdlet, which will parse the data into a usable format.

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

If your CSV file has missing headers, you might encounter warnings. To suppress these warnings, append -WarningAction SilentlyContinue to the command:

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

Step 2: Determine the Number of Real Columns

You can find out how many columns have actual data by checking the properties of the first row after importing.

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

Step 3: Export the Data Back to a New CSV File

Once you have read the data and verified the number of columns, the next task is to write it back into a clean CSV format. Use the Export-Csv cmdlet:

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

Resulting Output

This code will effectively create a new CSV file that retains only the valid headers while stripping out empty columns. You can expect an output like:

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

Note how the blank header has been replaced with a generic label like "H1".

Conclusion

By utilizing PowerShell, you can effectively manage CSV files, bringing more clarity to your data handling processes. This guide provides a clear method to read a CSV file, filter out unnecessary columns, and rewrite it into a clean format. Whether you're working with small or large data sets, these skills will undoubtedly prove valuable.

Feel free to adapt and apply this technique to your specific needs!