# Parameter Path

"parameter" atau "variabel" path didefinisikan dengan sintaksis Python format string:

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

Nilai parameter path `item_id` akan dikirim ke fungsi sebagai argument `item_id`:

Jika anda menjalankan contoh berikut dan kunjungi <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, anda akan melihat respon:

```JSON

# Environment Variables { #environment-variables }

/// tip

If you already know what "environment variables" are and how to use them, feel free to skip this.

///

An environment variable (also known as "**env var**") is a variable that lives **outside** of the Python code, in the **operating system**, and could be read by your Python code (or by other programs as well).

Aprenderás más sobre cómo usar variables de entorno para manejar **configuraciones de aplicación** en la [Guía del Usuario Avanzado - Ajustes y Variables de Entorno](./advanced/settings.md){.internal-link target=_blank}.

## Variable de Entorno `PATH`

Hay una variable de entorno **especial** llamada **`PATH`** que es utilizada por los sistemas operativos (Linux, macOS, Windows) para encontrar programas a ejecutar.

$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python

// But if we create an environment variable first
$ export MY_NAME="Wade Wilson"

// And then call the program again
$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

<div class="termy">

```console
// Aqui ainda não definimos a variável de ambiente
$ python main.py

// Como não definimos a variável de ambiente, obtemos o valor padrão

Hello World from Python

// Mas se criarmos uma variável de ambiente primeiro
$ export MY_NAME="Wade Wilson"

// E então chamar o programa novamente
$ python main.py

// Agora ele pode ler a variável de ambiente

Hello Wade Wilson from Python
```

$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python

// But if we create an environment variable first
$ export MY_NAME="Wade Wilson"

// And then call the program again
$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

# Omgevingsvariabelen

/// tip

Als je al weet wat "omgevingsvariabelen" zijn en hoe je ze kunt gebruiken, kun je deze stap gerust overslaan.

///

Een omgevingsvariabele (ook bekend als "**env var**") is een variabele die **buiten** de Python-code leeft, in het **besturingssysteem** en die door je Python-code (of door andere programma's) kan worden gelezen.

在許多情況下，環境變數的用途和適用性可能不會立刻顯現。但是在開發過程中，它們會在許多不同的場景中出現，因此瞭解它們是非常必要的。

   * add the suppression to the whole method (which turns off checking for a large section of code),
   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the

:end
@rem End local scope for the variables with windows NT shell
if %ERRORLEVEL% equ 0 goto mainEnd

:fail
rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
rem the _cmd.exe /c_ return code!
set EXIT_CODE=%ERRORLEVEL%
if %EXIT_CODE% equ 0 set EXIT_CODE=1
if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
exit /b %EXIT_CODE%

:mainEnd