How to eliminate the looping from below code - list

Question

I would like to eliminate the loops for better coding and improved performance. So, in below code I need to eliminate loop for test1, test 2, test3.
var test1 = _testP.cdata1(id, sdate)
.Where(t => t.In != null).ToList();
var test2 = _testP.cdata2(id, sdate)
.groupBy(p => p.In.id)
.ToDictionary(p => p.Key, p => p.ToDictionary(q => q.Date, q => q));
var test3 = test1.Select(t =>
{
Dictionary<Date, ClassB> cds = null;
ClassB cd = null;
if (test2.TryGetValue(t.In.Id, out cds)
&& cds.TryGetValue(t.date, out cd))
{
return new Tuple<ClassB, ClassA>(cd, t);
}
return null;
}).Where(p => p != null).ToList();
public IEnumerable<ClassA> cdata1(id, sdate)
{
// do some operations
return listA //(listA is the list of all the elements of ClassA object)
}
public IEnumerable<ClassB> cdata2(id, sdate)
{
// do some operations
return listA //(listA is the list of all the elements of ClassB object)
}
public ClassA
{
public testp in { get; }
public Date date { get; }
// other variables
}
public ClassB
{
public testp in { get; }
public Date date { get; }
// other variables
}
Help me out on writing better code for the above snippet.