Get First & Last Day from CSV in VB.Net 📅

Learn how to extract the first and last day from a CSV file in VB.Net utilizing effective parsing techniques.
---
This video is based on the question https://stackoverflow.com/q/68910330/ asked by the user 'Иван Олександров' ( https://stackoverflow.com/u/11940865/ ) and on the answer https://stackoverflow.com/a/68910534/ provided by the user 'David' ( https://stackoverflow.com/u/1920035/ ) 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: Get first and last day from .csv with VB.Net

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

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Getting the First and Last Day from a CSV with VB.Net

When working with CSV files in VB.Net, one common task that may arise is extracting specific values, such as the first and last day from a column representing dates. This might become a challenge, particularly if you try to directly calculate the minimum and maximum values while iterating through the file. In this guide, we will explore a practical solution to this problem, ensuring your properties store the correct values from your CSV file.

Understanding the Problem

You have two properties, FirstDayOfCsv and LastDayOfCsv, which need to hold the minimum (earliest) and maximum (latest) days present in a date column of a CSV file. The code you've tried appears to iterate through the rows and is intended to assign values to these properties directly using .Min and .Max. However, you're encountering issues since these functions are unable to operate directly in the manner you've coded.

Let’s look closely at your current code:

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

The problem here is that days.ToString("dd") doesn’t build a collection of dates to evaluate for minimum or maximum. Instead, we need a different approach to correctly obtain the first and last days.

Proposed Solution

Step-by-Step Breakdown

Read the CSV: First, read the CSV file and skip the header.

Initialize a Collection: Instead of trying to find the min and max while iterating, we’ll store the day values in a collection.

Convert and Add Values: Convert the string values to integers and add them to the list.

Calculate Min and Max: Finally, you can call .Min() and .Max() on your list after completing the loop.

Sample Code

Here’s how you can implement these steps in your VB.Net application:

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

Explanation

Line 1: We read all the lines from the CSV into an array, skipping the header row.

Line 2: We initialize a list everyday to hold the integer representations of the days.

Lines 3-8: The loop goes through each line, splitting the content of the line by semicolons to extract the date. Using Integer.TryParse, it checks if the conversion succeeds, and if so, adds it to the list.

Lines 10-11: Once the loop is complete, you simply assign the minimum and maximum values to your properties.

Conclusion

By leveraging a collection to store your data, you can easily compute the first and last days from your CSV file without falling into pitfalls of directly invoking Min and Max on string variables. The code we discussed not only accomplishes your goal but also enhances readability and maintainability.

Now you have a structured method to solve the problem effectively, enabling your VB.Net application to handle CSV parsing with ease. If you have any further questions or challenges, feel free to ask!