Determine if string ends in whitespace

Question

Given a string that ends in a whitespace character return true.

I'm sure I should be able to do this with regular expressions but I'm not having any luck. MSDN reference for regular expressions tells me that \s should match on a whitespace, but I can't figure the rest out.

Answer 1

How about

.+\s$

Answer 2

$ marks the end of the target on the pattern:

\s$

Answer 3

Like this:

if (Regex.IsMatch(someString, @"\s+$"))

• \s matches whitespace
• + means one or more of the preceding expression
  (one or more whitespace characters)
• $ means the end of the string

Answer 4

You certainly can use a regex for this, and I'm sure someone smarter than me will post exactly how to do it :), but you probably don't want to use a regex in this case. It will almost certainly be faster to simply ensure that the string is not null or empty, and then to return

Char.IsWhiteSpace(myString[length - 1])