DaxSharp 0.5.5

DaxSharp

DaxSharp is a .NET utility library that brings DAX-style summarization capabilities to LINQ collections. It offers flexible grouping, filtering, and aggregation of in-memory data structures in a concise, expressive way.

📦 Installation

Install via NuGet:

dotnet add package DaxSharp

🚀 Features

• Perform DAX-like SUMMARIZECOLUMNS on in-memory collections.
• Filter data before aggregation.
• Compute multiple aggregation expressions.
• Handle sparse or missing group combinations with Cartesian expansion.

🧪 Usage

SummarizeColumns

Groups and filters items, then computes specified aggregations.

using DaxSharp;
var data = new[]
{
    (Product: "Product1", Category: "Category1", IsActive: true, Amount: 10, Quantity: 2),
    (Product: "Product1", Category: "Category2", IsActive: true, Amount: 20, Quantity: 3),
    (Product: "Product2", Category: "Category1", IsActive: true, Amount: 5, Quantity: 1),
    (Product: "Product3", Category: "Category3", IsActive: true, Amount: 15, Quantity: 2)
}.ToList();

var results = data.SummarizeColumns(
    item => new { item.Product, item.Category },
    (item, group) => item is { IsActive: true, Category: not "Category1" } || group is { Category: not "Category1" },
    (items, group) =>
        items.ToArray() is { Length: > 0 } array
            ? array.Sum(x => x.Amount)
            : 2
);

The results are:

• Product1, Category2, 20
• Product3, Category3, 15.

SummarizeColumnsCartesian

Same as SummarizeColumns, but includes all combinations of group keys when aggregations on missing data aren't all null or zero.

using DaxSharp;
var data = new[]
{
    (Product: "Product1", Category: "Category1", IsActive: true, Amount: 10, Quantity: 2),
    (Product: "Product1", Category: "Category2", IsActive: true, Amount: 20, Quantity: 3),
    (Product: "Product2", Category: "Category1", IsActive: true, Amount: 5, Quantity: 1),
    (Product: "Product3", Category: "Category3", IsActive: true, Amount: 15, Quantity: 2)
}.ToList();

var results = data.SummarizeColumnsCartesian(
    item => new { item.Product, item.Category },
    (item, group) => item is { IsActive: true, Category: not "Category1" } || group is { Category: not "Category1" },
    (items, group) =>
        items.ToArray() is { Length: > 0 } array
            ? array.Sum(x => x.Amount)
            : 2
);

The results are:

• Product1, Category2, 20
• Product2, Category2, 2
• Product3, Category2, 2
• Product1, Category3, 2
• Product2, Category3, 2
• Product3, Category3, 15.

🛠️ API Reference

SummarizeColumns<T, TGrouped, TExpressions>

IEnumerable<(TGrouped grouped, TExpressions expressions)>
    SummarizeColumns<T, TGrouped, TExpressions>( 
        this IEnumerable<T> items,
        Func<T, TGrouped> groupByBuilder,
        Func<T?, TGrouped?, bool> filter,
        Func<IEnumerable<T>, TGrouped?, TExpressions?> expressions,
        int maxCount = int.MaxValue)
        where TGrouped : notnull

SummarizeColumnsCartesian<T, TGrouped, TExpressions>

IEnumerable<(TGrouped grouped, TExpressions expressions)>
    SummarizeColumnsCartesian<T, TGrouped, TExpressions>( 
        this IEnumerable<T> items,
        Func<T, TGrouped> groupByBuilder,
        Func<T?, TGrouped?, bool> filter,
        Func<IEnumerable<T>, TGrouped?, TExpressions?> expressions,
        int maxCount = int.MaxValue)
        where TGrouped : notnull

⚙️ Internals

Cartesian expansion in SummarizeColumnsCartesian fills in missing group key combinations with default expression results.

Skips results with all null expressions unless expansion is required.

📄 License

MIT