LINQ Operators

[This is preliminary documentation and is subject to change.]

The Condensed Library provides a set of specialized LINQ operators that can be much more efficient with large collections than the standard ones provided by System.Linq.

Using Specialized LINQ Operators

To use the specialized extension methods, add a "using Condensed.Linq;" statement to your source files that need to use them:

Copy

using System;
using Condensed;
using Condensed.Linq;

class Program
{
    static void Main()
    {
        // Add 100 million dates spanning December 2016:
        var cc = new CondensedCollection<DateTime>(capacity: 100000000);
        for (int i = 0; i < 100000000; i++)
            cc.Add(new DateTime(2016, 12, i % 30 + 1));

        // Count the Tuesdays in our collection:
        var tuesCount = cc.Count(d => d.DayOfWeek == DayOfWeek.Tuesday);
        // 13,333,333
    }
}

In addition to memory savings, LINQ operators are a core part of the collection's value proposition. The Count call in the sample above takes approximately 0.002 seconds to run on a 2015 laptop. The same logic takes over 5 seconds to execute against an ordinary List<T> collection. Specialized operators take advantage of the CondensedCollection's built-in knowledge of unique values and internal reference counting to improve the performance of many LINQ operations.

The trade-off is that loading the CondensedCollection typically takes anywhere from 2-10x longer than loading an ordinary List<T>, depending on the type and the quality of its equality comparer.

The following operators are currently supported in the initial alpha release, with more on way:

All
Any
Average
Contains
Count
Distinct
First
FirstOrDefault
Last
LastOrDefault
Max
Min
Sum