30 lines
980 B
Markdown
30 lines
980 B
Markdown
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---
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title: Select
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localeTitle: 选择
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---
# 选择
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从数据集中投射数据。
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### 签名
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```csharp
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Enumerable.Select<TSource, TResult> Method (IEnumerable<TSource>, Func<TSource, TResult>)
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```
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## 例
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```csharp
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var fruits = new List<Fruit>() {
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new Fruit() { Id = 1, Name = "Orange", Color = "Orange", Quantity = 3 },
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new Fruit() { Id = 2, Name = "Strawberry", Color = "Red", Quantity = 12 },
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new Fruit() { Id = 3, Name = "Grape", Color = "Purple", Quantity = 25 },
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new Fruit() { Id = 4, Name = "Pineapple", Color = "Yellow", Quantity = 1 },
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new Fruit() { Id = 5, Name = "Apple", Color = "Red", Quantity = 5 },
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new Fruit() { Id = 6, Name = "Mango", Color = "Yellow", Quantity = 2 }
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};
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var mangoQnt = fruits.Where(f => f.Name == "Mango").Select(f => f.Quantity).FirstOrDefault(); // 2
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var grapeColor = fruits.Where(f => f.Name == "Grape").Select(f => f.Color).FirstOrDefault(); // Purple
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```
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