# 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).

		"Missing credential environment variable, \""+EnvRootUser+"\"",
		"Environment variable \""+EnvRootUser+"\" is missing",
		`Root user name (access key) and root password (secret key) are expected to be specified via environment variables MINIO_ROOT_USER and MINIO_ROOT_PASSWORD respectively`,
	)

	ErrMissingEnvCredentialRootPassword = newErrFn(
		"Missing credential environment variable, \""+EnvRootPassword+"\"",

#### Listas

Por ejemplo, vamos a definir una variable para que sea una `list` compuesta de `str`.

De `typing`, importa `List` (con una `L` mayúscula):

```Python hl_lines="1"
{!../../docs_src/python_types/tutorial006.py!}
```

Declara la variable con la misma sintaxis de los dos puntos (`:`).

Pon `List` como el tipo.

### Classes en tant que types

Vous pouvez aussi déclarer une classe comme type d'une variable.

Disons que vous avez une classe `Person`, avec une variable `name` :

{*../../docs_src/python_types/tutorial010.py hl[1:3] *}


Vous pouvez ensuite déclarer une variable de type `Person` :

{*../../docs_src/python_types/tutorial010.py hl[6] *}

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

/**
 * The Interpolator service provides methods for variable substitution in strings and maps.
 * It allows for the replacement of placeholders (e.g., ${variable}) with their corresponding values.
 *
 * @since 4.0.0
 */
@Experimental
public interface Interpolator extends Service {

    /**

#### Liste

Definieren wir zum Beispiel eine Variable, die eine `list` von `str` – eine Liste von Strings – sein soll.

//// tab | Python 3.9+

Deklarieren Sie die Variable mit der gleichen Doppelpunkt-Syntax (`:`).

Als Typ nehmen Sie `list`.

# variables in it, OR may be left empty if the user has already exported the
# relevant variables in their environment. Because of 'set -o allexport' above
# (which is equivalent to "set -a"), every variable in the file is exported
# for other files to use.
#
# Separately, if TFCI is set *and* there are also additional TFCI_ variables

<p>
Computer architectures may require memory addresses to be <i>aligned</i>;
that is, for addresses of a variable to be a multiple of a factor,
the variable's type's <i>alignment</i>.  The function <code>Alignof</code>
takes an expression denoting a variable of any type and returns the
alignment of the (type of the) variable in bytes.  For a variable
<code>x</code>:
</p>

<pre>
uintptr(unsafe.Pointer(&amp;x)) % unsafe.Alignof(x) == 0

	}
}

func serverHandleEnvVars() {
	var err error
	if globalBrowserEnabled {
		if redirectURL := env.Get(config.EnvBrowserRedirectURL, ""); redirectURL != "" {
			u, err := xnet.ParseHTTPURL(redirectURL)
			if err != nil {
				logger.Fatal(err, "Invalid MINIO_BROWSER_REDIRECT_URL value in environment variable")
			}

local g = import './g.libsonnet';
local var = g.dashboard.variable;

{
  datasource:
    var.datasource.new('datasource', 'prometheus'),

  cluster:
    var.query.new('cluster')
    + var.query.withDatasourceFromVariable(self.datasource)
    + var.query.queryTypes.withLabelValues(
      'cluster',
      'process_cpu_seconds_total',
    )
    + var.query.withRefresh('time')
    + var.query.selectionOptions.withMulti()