Question

Is there a way to write a single LINQ expression to get the same result of the following code?

        var validations = new Func<conversion, bool>[] { 
             c => c.affiliate.affiliate_id > 0,
             c => c.campaign_id > 0
        }; 

        var invalidConversions = from c in extractedConversions
                                 where validations.Any(valid => !valid(c))
                                 select c;

        var validConversions = from c in extractedConversions
                               where validations.All(valid => valid(c))
                               select c;

Answer 1

Well you could use something like:

var partitioned = extracted.ToLookup(c => validations.All(valid => valid(c)));

Then:

// Valid conversions
foreach (var valid in partitioned[true])
{
}

// Invalid conversions
foreach (var invalid in partitioned[false])
{
}

You could use GroupBy as well, but ToLookup materializes the results immediately and gives you a handy way of accessing them, which I suspect is what you want here.