## `async` and `await` { #async-and-await }

Modern versions of Python have a very intuitive way to define asynchronous code. This makes it look just like normal "sequential" code and do the "awaiting" for you at the right moments.

When there is an operation that will require waiting before giving the results and has support for these new Python features, you can code it like:

```Python
burgers = await get_burgers(2)
```

</div>

////

## Ler Variáveis de Ambiente no Python { #read-env-vars-in-python }

Você também pode criar variáveis de ambiente **fora** do Python, no terminal (ou com qualquer outro método) e depois **lê-las no Python**.

Por exemplo, você poderia ter um arquivo `main.py` com:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip | Dica

Beachten Sie, wie wir `CommonQueryParams` im obigen Code zweimal schreiben:

//// tab | Python 3.10+

```Python
commons: Annotated[CommonQueryParams, Depends(CommonQueryParams)]
```

////

//// tab | Python 3.10+ nicht annotiert

/// tip | Tipp

Bevorzugen Sie die `Annotated`-Version, falls möglich.

///

```Python
commons: CommonQueryParams = Depends(CommonQueryParams)
```

////

Hello Wade Wilson
```

</div>

////

## 在 Python 中讀取環境變數 { #read-env-vars-in-python }

你也可以在 Python **之外**的終端機中建立環境變數（或使用其他方法），然後在 Python 中**讀取**它們。

例如，你可以建立一個名為 `main.py` 的檔案，其中包含以下內容：

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip

第二個參數是 [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) 的預設回傳值。

<div class="termy">

```console
$ python -m venv .venv
```

</div>

/// details | Що означає ця команда

* `python`: використати програму з назвою `python`
* `-m`: викликати модуль як скрипт, далі ми вкажемо, який модуль
* `venv`: використати модуль з назвою `venv`, який зазвичай уже встановлено з Python

<div class="termy">

```console
$ which python

/home/user/code/awesome-project/.venv/bin/python
```

</div>

Si muestra el binario de `python` en `.venv/bin/python`, dentro de tu proyecto (en este caso `awesome-project`), entonces funcionó. 🎉

////

//// tab | Windows PowerShell

<div class="termy">

```console
$ Get-Command python

<div class="termy">

```console
$ which python

/home/user/code/awesome-project/.venv/bin/python
```

</div>

Se ele mostrar o binário `python` em `.venv/bin/python`, dentro do seu projeto (neste caso `awesome-project`), então funcionou. 🎉

////

//// tab | Windows PowerShell

<div class="termy">

```console
$ Get-Command python

<div class="termy">

```console
$ python myapp.py
```

</div>

mas não é chamado quando outro arquivo o importa, como em:

```Python
from myapp import app
```

#### Mais detalhes { #more-details }

Digamos que seu arquivo se chama `myapp.py`.

Se você executá-lo com:

<div class="termy">

```console
$ python myapp.py
```

</div>

```Python
user_in = UserIn(username="john", password="secret", email="******@****.***")
```

et que nous appelons ensuite :

```Python
user_dict = user_in.model_dump()
```

nous avons maintenant un `dict` avec les données dans la variable `user_dict` (c'est un `dict` au lieu d'un objet modèle Pydantic).

Et si nous appelons :

```Python
print(user_dict)
```

<div class="termy">

```console
$ python myapp.py
```

</div>

mais qui n'est pas appelé lorsqu'un autre fichier l'importe, comme dans :

```Python
from myapp import app
```

#### Pour davantage de détails { #more-details }

Imaginons que votre fichier s'appelle `myapp.py`.

Si vous l'exécutez avec :

<div class="termy">

```console
$ python myapp.py
```

</div>