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从路径中捕获变量

在路由中使用尖括号参数

从路径中捕获变量 是 CoddyKit 上的免费 Flask Academy 课时。这是第 1 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 Flask Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Flask 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。

Static Routes Hit a Wall

A fixed path like /user/alice only works for one person. To serve any name, you need a route that captures part of the URL as data.

Angle Brackets Capture Values

Wrap a path segment in angle brackets to turn it into a variable. Flask grabs whatever the user types there and hands it to your view as a parameter. 🎯

@app.route('/user/<name>')
def profile(name):
    return f'Hello, {name}!'

The Name Must Match

The word inside the brackets becomes the function argument. The name in the URL and the parameter in your view function must be spelled identically.

@app.route('/city/<place>')
def show(place):
    return place

Values Arrive as Strings

By default a captured value is always a Python string. Visiting /user/42 gives you the text "42", not the number 42.

@app.route('/id/<value>')
def show(value):
    return type(value).__name__

Capture More Than One

A single route can capture several segments. Each set of angle brackets becomes its own argument in the view function, in order.

@app.route('/<category>/<item>')
def show(category, item):
    return f'{category}: {item}'

Mix Fixed and Dynamic Parts

You can blend static text with captured pieces. Only the bracketed segment is dynamic; the rest of the path stays fixed and literal.

@app.route('/posts/<slug>/edit')
def edit(slug):
    return slug

Use the Value in Your Logic

Once captured, the variable is just normal Python. Look it up in a database, format it, or branch on it like any other value.

@app.route('/user/<name>')
def hi(name):
    return f'Welcome back, {name.title()}'

Each Request Is Independent

Every visit fills the captured variable fresh. One user hitting /user/sam and another hitting /user/lee get separate, isolated requests.

Slashes Split Segments

A normal capture stops at the next slash. So name in /user/<name> will not include any /, since the slash marks the end of that segment.

Naming Your Variables Well

Pick clear names that describe the data, like <username> or <product_id>. Good names make routes self-documenting and easier to maintain.

A Tiny Real Example

Captured variables power friendly URLs like /greet/Maria. The view simply uses the value to build a personalized response for each visitor.

@app.route('/greet/<who>')
def greet(who):
    return f'Nice to meet you, {who}'

Quick Check

You wrote /user/<name> with def profile(name). What gets passed to name?

Recap: You Captured the Path

Angle brackets turn part of a URL into a function argument. Captured values arrive as strings, and you can grab several at once. Next: typing them. 🚀

常见问题解答

「从路径中捕获变量」课时是免费的吗？

是的 — 「从路径中捕获变量」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 Flask Academy 课程的其余内容，请升级到 CoddyKit PRO。 Flask Academy 课程共包含 4 节课。

「从路径中捕获变量」这节课中我会学到什么？

在路由中使用尖括号参数你通过在浏览器中直接运行的动手代码来练习 Flask 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 Flask Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Flask 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 1 节课，共 4 节。

「从路径中捕获变量」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 Flask Academy 课中编写并运行代码吗？

能。每节 Flask 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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