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使用 try/except 捕获错误

优雅地从失败中恢复

使用 try/except 捕获错误 是 CoddyKit 上的免费 Mojo Academy 课时。 这是第 2 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。

Catching the Fall

Raising signals a problem, but someone must catch it. Mojo uses a try block to run risky code and recover if it fails. 🪤

The try Block

Code that might fail goes inside try. If it raises, Mojo jumps straight to the matching recovery code below.

try:
    risky_step()

The except Block

The except block holds your recovery plan. It only runs when the try block actually raised an error.

try:
    risky_step()
except:
    print("recovered")

Reading the Error

You can name the caught error to read its message. Here e holds the details of what went wrong.

try:
    risky_step()
except e:
    print("failed:", e)

Normal Path First

If nothing raises, the try block finishes and the except block is skipped entirely. The happy path stays clean.

Recovering Gracefully

Catching lets you show a friendly message or use a fallback value instead of letting the whole program crash. ✨

Keep try Blocks Small

Wrap only the risky line in try, not your whole function. Small blocks make it clear what could fail.

Catching Calls That Raise

Calling a function that may raise requires a try. Here we safely attempt a withdrawal and handle a rejection.

try:
    withdraw(-5)
except e:
    print("denied:", e)

Don't Swallow Silently

An empty except that does nothing hides bugs. At minimum log the error so problems stay visible.

Catch Where You Can Help

Only catch an error where you can actually do something useful about it. Otherwise let it propagate upward.

Try Plus Except as a Pair

Together try and except turn a possible failure into a controlled outcome your program can continue past.

Quick Check

Recall when each block of a try/except actually runs.

Recap

You learned to wrap risky code in try, recover in except, read the error with a name, and keep blocks small and meaningful. 🎯

常见问题解答

「使用 try/except 捕获错误」课时是免费的吗？

是的 — 「使用 try/except 捕获错误」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。

「使用 try/except 捕获错误」这节课中我会学到什么？

优雅地从失败中恢复 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 2 节课，共 4 节。

「使用 try/except 捕获错误」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。

此课程中的所有课时

  1. 引发错误
  2. 使用 try/except 捕获错误
  3. raises 注解
  4. 使用 finally 清理
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