GroupBy a combination of columns - changes .Select

hi, 

having bit of trouble lamda expression.  i wish groupby combination of couple of columns , select single column.  however whatever group seems going 'key'.  

e.g. need group hour+timetype select hour

 

void main() { 	list<hours> hrs = gettimes(); 	hrs.dump(); 	 	list<string> hrlist = hrs 		.groupby (grp1 => string.format("{0}{1}" , grp1.timetype, grp1.hour)) 		.select (grp => grp.key.tostring()).tolist(); 	  	hrlist.dump();					 }  public class hours  { 	public string hour { get; set; } 	public string timetype { get; set; } }   public list<hours> gettimes() { 	list<hours> hrs = new list<hours>(); 	hrs.add(new hours() { timetype="am", hour="01"}); 	hrs.add(new hours() { timetype="am", hour="02"}); 	hrs.add(new hours() { timetype="am", hour="03"}); 	hrs.add(new hours() { timetype="am", hour="04"}); 	hrs.add(new hours() { timetype="am", hour="05"}); 	hrs.add(new hours() { timetype="pm", hour="01"}); 	hrs.add(new hours() { timetype="pm", hour="02"}); 	hrs.add(new hours() { timetype="pm", hour="03"}); 	return hrs;  } 

this gives me: 

am01

am02

am03

am04

am05

pm01

pm02

pm03

the problem that, in groupby clase, creating single key, combination of timetype and hour fields. instead, must specify them separately:

list<string> hrlist = hrs      .groupby(grp1 => new { grp1.timetype, grp1.hour })      .select(grp => grp.key.hour).tolist();

in way, in select lambda expression can specify hour value only.

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marco minerva [mcpd]
blog: http://blogs.ugidotnet.org/marcom
twitter: @marcominerva

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