DaxSharp 0.5.4

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 result = data.SummarizeColumnsCartesian(
    [
        item => item.Product,
        item => item.Category
    ],
    array => (product: array[0], category: array[1] as string),
    (item, g) => item.IsActive && g.category != "Category1",
    (items, g) =>
        items.ToArray() is { Length: > 0 } array
        ? array.Sum(x => x.Amount)
        : 2
);

SummarizeColumnsCartesian

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

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 result = data.SummarizeColumnsCartesian(
    [
        item => item.Product,
        item => item.Category
    ],
    array => (product: array[0], category: array[1] as string),
    (item, g) => item.IsActive && g.category != "Category1",
    (items, g) =>
        items.ToArray() is { Length: > 0 } array
        ? array.Sum(x => x.Amount)
        : 2
);

🛠️ API Reference SummarizeColumns<T, TGrouped, TExpressions>

IEnumerable<(TGrouped grouped, TExpressions expressions)> SummarizeColumns<T, TGrouped, TExpressions>(
this IEnumerable<T> items,
IEnumerable<Func<T, object?>> groupByKeys,
Func<object?[], TGrouped> groupByBuilder,
Func<T, TGrouped?, bool> filter,
Func<IEnumerable<T>, TGrouped?, TExpressions?> expressions)
where TGrouped : notnull

SummarizeColumnsCartesian<T, TGrouped, TExpressions>

IEnumerable<(TGrouped? grouped, TExpressions expressions)> SummarizeColumnsCartesian<T, TGrouped, TExpressions>(
this IEnumerable<T> items,
IEnumerable<Func<T, object?>> groupByKeys,
Func<object?[], TGrouped?> groupByBuilder,
Func<T, TGrouped?, bool> filter,
Func<IEnumerable<T>, TGrouped?, TExpressions?> expressions,
int maxCount = int.MaxValue,
Func<T, TGrouped?>? optimizedGroupByBuilder = null)
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