Question

In C#, how do I find all the words starting with ‘$’ sign and ending with space, in a long string, using regular expressions?

Answer 1

Try:

var matches = Regex.Matches(input, "(\\$\\w+) ");

In the above, \\w matches word characters. These are A-Z, a-z, – and _ if I’m correct. If you want to match everything that’s not a space, you can use \\S. If you want a specific set, specify this through e.g. [a-zA-Z0-9].

The brackets around the (\\$\\w+) ensures that of a specific match, matches[0].Groups[1].Value; gives the value inside the backets (so, excluding the trailing space).

As a complete example:

string input = "$a1 $a2 $b1 $b2";

foreach (Match match in Regex.Matches(input, "(\\$\\w+) "))
{
    Console.WriteLine(match.Groups[1].Value);
}

This produces the following output:

$a1
$a2
$b1

The $b2 is of course omitted because it does not have a trailing space.