The Daily WTF: Curious Perversions in Information Technology

2026-10-22 Reply Admin

TRWTF is not allowing "#0.## \u2030" like in Java.

2026-10-22 Reply Admin

This looks like they're trying to set-up an interpolated string (i.e.: $"{0:#,##0.00;(#,##0.00)}", which would just result in "0.00;(0.00)"). But as far as I know, you can't use interpolated strings like this:

string str = $"{myfield.DataFormatString}"; //Won't work, or at least won't print "0.00;(0.00)"

But maybe this isn't C#, and it works just fine in whatever language they're using.

adamantoise · 2026-10-22 Reply Edit Admin

If you're typing it frequently, you can use Option+Shift+R to type ‰ on macOS. But let's be honest, 99.999% of people (or 999.99‰ of people?) aren't typing it frequently and are going to have to google it, like I did just now.

WTFGuy · 2026-10-22 Reply Edit Admin

It's probably C# and I doubt they're trying to use the $ syntax. IMO more likely it's like this:

myField.DataFormatString = "{0:#,##0. ... }";  // assume this a valid format string.
...
// much later elsewhere in the code
myTextBox.Text = String.Format (Myfield.DataFormatString, myField.Value);

And you're correct about the $ syntax. MSFT says only works with a literal string. It's a compile-time transformation into formatting calls. See the first sentence here: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/interpolated

2026-10-22

Comment held for moderation.

Barry Margolin · 2026-10-22 Reply Edit Admin

The designers of C printf realized long ago that you sometimes need to parameterize some of the formatting options, so you can use * in place of things like the field width to get the value from the arguments. This doesn't handle all the cases where you need to build format strings dynamically, but it gets the most common ones.

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