c# - how can i count duplicates in a list and change the item value -

i have program generates 3 lists based on contents of text file. want @ list , if there's item in more once, i'd change value "number in list x item" , remove duplicates list.

here code use open , split file lists:

    private void open_click(object sender, eventargs e)     {         if (inputfile.showdialog() == dialogresult.ok)         {          var reader = new streamreader(file.openread(inputfile.filename));          while (!reader.endofstream)              {                  string line = reader.readline();                  if (string.isnullorempty(line)) continue;                  if (line.startswith("#main"))                  {                      deck = "main";                  }                  if (deck == "main")                  {                      if (!line.startswith("#"))                      {                          int cardid = convert.toint32(line.substring(0));                          maindeck.items.add(program.carddata[cardid].name);                      }                  }                  if (line.startswith("#extra"))                  {                      deck = "extra";                  }                  if (deck == "extra")                  {                      if (!line.startswith("#extra") && !line.startswith("!side"))                      {                          int cardid = convert.toint32(line.substring(0));                          extradeck.items.add(program.carddata[cardid].name);                      }                  }                   if (line.startswith("!side"))                  {                      deck = "side";                  }                  if (deck == "side")                  {                      if (!line.startswith("!side"))                      {                          int cardid = convert.toint32(line.substring(0));                          sidedeck.items.add(program.carddata[cardid].name);                      }                  }             }          reader.close();          generatecode();         }     } 

in other words item "hello" in list 3 times: want change in list once , "3x hello".

use enumerable.distinct remove duplicates:

maindeck = maindeck.distinct().tolist(); extradeck = extradeck.distinct().tolist(); sidedeck = sidedeck.distinct().tolist(); 

if want count duplicates first:

int maindeckdups = maindeck.count - maindeck.distinct().count(); int extradeckdups = extradeck.count - extradeck.distinct().count(); int sidedeckdups = sidedeck.count - sidedeck.distinct().count(); 

if want show how many times item in list use enumerable.groupby, e.g.:

var maindeckgroups = maindeck.groupby(s => s)     .select(g => new { item = g.key, count = g.count() })     .where(x => x.count > 1)     .orderbydescending(x => x.count); foreach (var dup in maindeckgroups)     console.writeline("{0}x {1}", dup.count, dup.item); // other lists ...