C# Get substring with specific pattern from string

Question

I have a list of strings like this:

List<string> list = new List<string>();
list.Add("Item 1: #item1#");
list.Add("Item 2: #item2#");
list.Add("Item 3: #item3#");

How can I get and add the substrings #item1#, #item2# etc into a new list?

I am only able to get the complete string if it contains a "#" by doing this:

foreach (var item in list)
{
    if(item.Contains("#"))
    {
        //Add item to new list
    }
}

Answer 1

You could have a look at Regex.Match. If you know a little bit about regular expressions (in your case it would be a quite simple pattern: "#[^#]+#"), you can use it to extract all items starting and ending with '#' with any number of other characters other than '#' in between.

Example:

Match match = Regex.Match("Item 3: #item3#", "#[^#]+#");
if (match.Success) {
    Console.WriteLine(match.Captures[0].Value); // Will output "#item3#"
}

Answer 2

Here's another way using a regex with LINQ. (Not sure your exact requirements reference the regex, so now you may have two problems.)

var list = new List<string> ()
{
    "Item 1: #item1#",
    "Item 2: #item2#",
    "Item 3: #item3#",
    "Item 4: #item4#",
    "Item 5: #item5#",
};

var pattern = @"#[A-za-z0-9]*#";

list.Select (x => Regex.Match (x, pattern))
    .Where (x => x.Success)
    .Select (x => x.Value)
    .ToList ()
    .ForEach (Console.WriteLine);

Output:

#item1#

#item2#

#item3#

#item4#

#item5#