Question

during my coding I’ve come across a problem that involved parsing a string like this:

{15} there are 194 red balloons, {26} there are 23 stickers, {40} there are 12 jacks, ….

my code involved pulling both the sentence and the number into two separate arrays.
I’ve solved the problem involving parsing out the sentence into its own array using a *.Remove(0, 5) to eliminate the first part the problem with that part was that I had to make sure that the file always was written to a standard where {##} where involved however it was not as elegant as I would like in that some times the number would be {3} and i would be forced to make it { 3}.

as there were also the chance of the string containing other numbers I wasn’t able to simply parse out the integers first.

int?[] array = y.Split(',')
            .Select(z =>
            {
                int value;
                return int.TryParse(z, out value) ? value : (int?)null;
            })
            .ToArray();

so anyway back to the problem at hand, I need to be able to parse out “{##}” into an array with each having its own element.

Answer 1

Here’s one way to do it using positive lookaheads/lookbehinds:

string s = "{15} there are 194 red balloons, {26} there are 23 stickers, {40} there are 12 jacks";

// Match all digits preceded by "{" and followed by "}"
int[] matches = Regex.Matches(s, @"(?<={)\d+(?=})")
    .Cast<Match>()
    .Select(m => int.Parse(m.Value))
    .ToArray(); 

// Yields [15, 26, 40]