Question

I separated “A320-789-890” according to “-” and i get a list below:

"A101C", "B7CL", "E7CL", "D7CL"

Everything is ok. My result set above it is my solution result. But i have 2 question:

1. how can I do that with regex?
2. if I can do that with regex, can I use regex with linq?

3. which is more effective according to performance like my method below, or regex?

   namespace engRegex1
   {
   public partial class Form1 : Form
   {
   public Form1()
   {
   InitializeComponent();
   }

       private void Form1_Load(object sender, EventArgs e)
       {
           Engineering eng = new Engineering();
           string[] engSplitList = new string[eng.engList.Count()];
           List<string> firstitem = new List<string>();
           foreach (string item in eng.engList)
           {
               engSplitList = item.Split('-');
               firstitem.Add(engSplitList[0]);
           }
           foreach (string item in firstitem)
               listBox1.Items.Add(item);
       }
   }
   public class Engineering
   {
       public List<string> engList = new List<string>() { 
           "A101C-234-456", "B7CL-567-789", "E7CL-567-789", "D7CL-567-789" };
   }
   

   }

Answer 1

As long as you need to extract just the first part I’m suggesting IndexOf + Subsstring:

foreach (string item in eng.engList)
{
    listBox1.Items.Add(item.Subsstring(0, item.IndexOf('-'));
}

It would be the fastest (and probably the easiest) way.

//EDIT
with LINQ it would something like that:

listBox1.Items.AddRange(from item in eng.engList select item.Subsstring(0, item.IndexOf('-')));

with RegEX

foreach (string item in eng.engList)
{
    listBox1.Items.Add(RegEx.Match(item, "[^-]*").ToString());
}

with RegEX and LINQ:

listBox1.Items.AddRange(from item in eng.engList select RegEx.Match(item, "[^-]*").ToString())