Скачать или смотреть Understanding the C# EndsWith Quirk: A Guide to Correct String Comparisons

Discover why C# 's `EndsWith` method may return unexpected results and learn how to ensure accurate string comparisons using ordinal settings.
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This video is based on the question https://stackoverflow.com/q/68467553/ asked by the user 'Jánosi Zoltán János' ( https://stackoverflow.com/u/6517599/ ) and on the answer https://stackoverflow.com/a/68468683/ provided by the user 'CSharpie' ( https://stackoverflow.com/u/1789202/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the C# EndsWith Quirk: A Guide to Correct String Comparisons

C# developers often encounter tricky situations when working with string methods such as EndsWith. A common frustration arises when the method returns unexpected results due to culture-specific settings. In this guide, we’ll explore a specific instance where users have reported the EndsWith method giving false results and how to rectify it effectively.

The Problem

In a recent scenario, a user noticed that calling EndsWith on specific strings produced inconsistent results. Here’s a brief overview of the code that led to the confusion:

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

Output Observations

When the code was executed, the results showed that:

Strings like "s", "As", "Ds" returned True for ending with "s".

However, "Cs" and "cs" returned False when checked with EndsWith("s").

It was puzzling since all other small and capital variations returned the expected True.

Environment and Observations

The user noticed discrepancies across different frameworks and environments, such as:

.NET 4.x versions (produced error)

.NET 3.0, 3.5, and even .NET 6.0 (produced the same problem in VS2022)

Dotnetfiddle using .NET 4.7.2 (which worked without issues)

The Cause of the Problem

The root of the problem stems from cultural differences in string comparison. By default, EndsWith respects the current culture settings, which can sometimes lead to unexpected behavior. Since the user pointed out that their settings might be in Hungarian, it likely affected how EndsWith evaluated the character comparisons.

Key Takeaway

It's important to note that the default string comparison often leads to inconsistencies when working with various character cases and languages due to specific cultural rules.

The Solution

The most straightforward solution to ensure that EndsWith operates correctly across all scenarios is to use ordinal comparison. This approach disregards cultural settings and focuses solely on the binary values of characters.

Here’s how to implement the change in the code:

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

Benefits of Using Ordinal Comparison

Consistency: No more unexpected results from culture-specific string evaluations.

Performance: Ordinal comparison is generally faster than culture-based comparisons since it involves a simpler check on the binary representation of characters.

Conclusion

When working with string methods in C# , it’s vital to understand the implications of cultural settings on function outcomes. By utilizing ordinal string comparison, developers can achieve reliable and consistent results across different environments.

Remember, if you encounter similar issues like unexpected results from EndsWith, consider checking the string comparison settings and switch to StringComparison.Ordinal to get the reliable behavior you need.

Feel free to share your experiences or questions in the comments below. Happy coding!