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moveinit 方法

定义类型如何移动自身

__moveinit__ 方法 是 CoddyKit 上的免费 Mojo Academy 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Mojo Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Mojo Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Defining How to Move

To move a value, Mojo calls a special method named __moveinit__. It builds a new instance by taking over an old one. 🚚

It Runs on Transfer

When you use the caret transfer operator, __moveinit__ fires. It relocates the value instead of duplicating its data.

var b = a^   # calls __moveinit__

The Method Signature

It receives the new instance and the owned source value. Because the source is owned, you may consume it directly.

fn __moveinit__(out self, owned existing: Self):
    self.ptr = existing.ptr

Steal, Do Not Copy

The trick is to transfer resources like a heap pointer from the source to the new instance, rather than allocating again.

No Double Free

After the move, the source must not free the data it gave away. Mojo handles this so the buffer is owned by exactly one instance.

Cheap for Big Values

Because __moveinit__ shuffles ownership instead of cloning bytes, moving a huge buffer costs almost nothing. That is the speed win.

Source Becomes Invalid

Once moved from, the source is consumed. Mojo stops you from reading it, guaranteeing you never touch relocated data.

Often Derived for You

Like copying, you usually do not write this. Conforming to Movable lets Mojo synthesize a field-wise __moveinit__ for you.

When to Write It Yourself

Customize __moveinit__ when your type owns a resource that needs explicit hand-off, such as a manually managed pointer.

Pairs with Copy

A type can define both copy and move. Mojo then picks the cheaper one, choosing a move whenever the source is no longer needed.

Enables Cheap Ownership

__moveinit__ is what makes ownership transfer fast and safe. It lets values flow through your program without wasteful duplication.

Quick Check

Lets check the move initializer.

Recap

__moveinit__ defines how your type moves, handing resources to a new instance cheaply and consuming the source. 🎯

常见问题解答

「moveinit 方法」课时是免费的吗？

是的 — 「__moveinit__ 方法」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Mojo Academy 课程的其余内容，请升级到 CoddyKit PRO。 Mojo Academy 课程共包含 4 节课。

「moveinit 方法」这节课中我会学到什么？

定义类型如何移动自身你通过在浏览器中直接运行的动手代码来练习 Mojo Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Mojo Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Mojo Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「moveinit 方法」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Mojo Academy 课中编写并运行代码吗？

能。每节 Mojo Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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