If i understand you correctly...
List<string[]> sta = new List<string[]>(){
new string[]{"station1", "debit"},
new string[]{"station1", "volume"},
new string[]{"station2", "pluit"},
new string[]{"station2", "debit"},
new string[]{"station3", "debit"},
new string[]{"station4", "debit"}};
var qry = sta.GroupBy(a=>a[0]).Select(grp=>new{station = grp.Key, count= grp.Count()});
foreach(var r in qry)
{
Console.WriteLine("{0} - {1}", r.station, r.count);
}
[EDIT]
In case of pipe "
|
" delimiter:
List<string> sta = new List<string>(){"station1|debit",
"station1|volume",
"station2|pluit",
"station2|debit",
"station3|debit",
"station4|debit"};
var qry = sta.Select(a=>Tuple.Create(a.Split('|')[0], a.Split('|')[1]))
.GroupBy(b=>b.Item1).Select(grp=>new{station=grp.Key, count = grp.Count()});