c# - How to group items in a list with the same max date and filter them -

i have list<takenbmi> these 4 columns , data:

takendate     uerid   takenitem   takenvalue aug-10-2014     34     weight       140 aug-10-2014     34     height       5.5 mar-15-2015     34     weight       141 mar-15-2015     34     height       5.5 

i want group them in separate lists based on takendate , find out list should use has details latest taken date.

here have tried:

var q = n in takenbmi          group n n.takendate g          select g.orderbydescending(t=>t.takendate )                 .firstordefault();   var m = n in takenbmi          group n n.takendate g          select new { takendate = convert.todatetime(q) }; 

also, if can suggest after getting list max date one, how 2nd latest date ones if possible? thank replied

i'd approach finding latest date:

var latestdate = items.select(i => i.takendate).max(); 

then filtering items date:

var itemswithlatestdate = items.where(i => i.takendate == latestdate).tolist(); 

if require of them grouped in date order, then:

var itemsbydate = items.groupby(i => i.takendate).orderby(g => g.key); 

the latest date group last of groups:

var itemswithlatestdate = itemsbydate.last();