你能命名 C# 7 Tuple 内联项吗?

Can you name C# 7 Tuple items inline?(你能命名 C# 7 Tuple 内联项吗?)

问题描述

默认情况下，使用 C# 7 元组时，项目将命名为 Item1、Item2 等.

By default, when using C# 7 tuples, the items will named like Item1, Item2, and so on.

我知道您可以命名方法返回的元组项.但是你能做同样的内联代码吗，比如下面的例子?

I know you can name tuple items being returned by a method. But can you do the same inline code, such as in the following example?

foreach (var item in list1.Zip(list2, (a, b) => (a, b)))
{
    // ...
}

在 foreach 的正文中，我希望能够访问末尾的元组(包含 a 和 b)使用比 Item1 和 Item2 更好的东西.

In the body of the foreach, I would like to be able to access the tuple at the end (containing a and b) using something better than Item1 and Item2.

推荐答案

可以，通过解构元组:

foreach (var (boo,foo) in list1.Zip(list2, (a, b) => (a, b)))
{
    //...
    Console.WriteLine($"{boo} {foo}");
}

或

foreach (var item in list1.Zip(list2, (a, b) => (a, b)))
{
    //...
    var (boo,foo)=item;
    Console.WriteLine($"{boo} {foo}");
}

即使您在声明元组时命名了字段，您也需要解构语法才能将它们作为变量访问:

Even if you named the fields when declaring the tuple, you'd need the deconstruction syntax to access them as variables:

foreach (var (boo,foo) in list1.Zip(list2, (a, b) => (boo:a, foo:b)))
{
    Console.WriteLine($"{boo} {foo}");
}

如果您想在不解构元组的情况下按名称访问字段，则必须在创建元组时为其命名:

If you want to access the fields by name without deconstructing the tuple, you'll have to name them when the tuple is created:

foreach (var item in list1.Zip(list2, (a, b) => (boo:a, foo:b)))
{
    Console.WriteLine($"{item.boo} {item.foo}");
}

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