LINQ — Animate | AI Wisdom

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🎞 ANIMATE · Mode 3 of 5 · +100 XP— LINQ in C#
📋Build
⚙️Defer
🔄GroupBy
✅Join
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Step 1 / 4
Speed
Build Query
Where/OrderBy/Select chain — query object, not results yet💡 Analogy
Like writing a shopping list before going to the store — the list is built without buying anything yet.
LINQ chains (Where, Select, OrderBy) build a query description, not the results. Nothing runs until you iterate (ToList, First, foreach).
Console Output
> query defined: Where + OrderBy + Select
> No iteration yet
> query.Expression: {...} (description only)
●LinqExamples.cs
Build QueryL10–14
1var orders = new List<Order>
2{
3    new(1, "Alice", 120.00m, "UK"),
4    new(2, "Bob",    45.00m, "US"),
5    new(3, "Alice", 230.00m, "UK"),
6    new(4, "Carol",  89.00m, "US"),
7};
8 
9// Deferred execution — query built but NOT run yet
10var query = orders
11    .Where(o => o.Total > 50)       // filter
12    .OrderByDescending(o => o.Total) // sort
13    .Select(o => new { o.Customer, o.Total }); // project
14 
15// Execution triggered here (ToList, First, Count, foreach)
16var results = query.ToList();
17// [{ Customer="Alice", Total=230 }, { Customer="Alice", Total=120 }]
18 
19// GroupBy — aggregate by customer
20var perCustomer = orders
21    .GroupBy(o => o.Customer)
22    .Select(g => new
23    {
24        Customer = g.Key,
25        OrderCount = g.Count(),
26        TotalSpent = g.Sum(o => o.Total),
27        AverageOrder = g.Average(o => o.Total),
28    })
29    .OrderByDescending(x => x.TotalSpent);
30 
31// Join — correlate two collections
32var regions = new[] { new Region("UK", "Europe"), new Region("US", "Americas") };
33var withRegion = orders.Join(
34    regions,
35    o => o.Country,             // left key
36    r => r.Code,                // right key
37    (o, r) => new { o.Customer, o.Total, r.Continent }
38);
38 lines
Timeline — 4 Steps
Build Query
Where/OrderBy/Select chain — query object, not results yet💡 Analogy
Like writing a shopping list before going to the store — the list is built without buying anything yet.
LINQ chains (Where, Select, OrderBy) build a query description, not the results. Nothing runs until you iterate (ToList, First, foreach).
Console Output
> query defined: Where + OrderBy + Select
> No iteration yet
> query.Expression: {...} (description only)

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Discussion

Where/OrderBy/Select chain — query object, not results yet

💡 Analogy

Like writing a shopping list before going to the store — the list is built without buying anything yet.

LINQ chains (Where, Select, OrderBy) build a query description, not the results. Nothing runs until you iterate (ToList, First, foreach).

Console Output

> query defined: Where + OrderBy + Select
> No iteration yet
> query.Expression: {...} (description only)

Where/OrderBy/Select chain — query object, not results yet

💡 Analogy

Like writing a shopping list before going to the store — the list is built without buying anything yet.

LINQ chains (Where, Select, OrderBy) build a query description, not the results. Nothing runs until you iterate (ToList, First, foreach).

Console Output

> query defined: Where + OrderBy + Select
> No iteration yet
> query.Expression: {...} (description only)