Accepted answer

for the count you just need this query:

int total = pieces
    .where(x => x.count > 0)
    .groupby(x => new { x.count,, x.description })
    .sum(g => g.key.count);

so you can access all key properties of the grouping.

this returns 85 for your initial sample and 108 if you add the new piece.

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