A ConfigSection represents one named group of config values such as [database], [app] or [stripe].

Working with sections is useful when a class needs several related values but should not be handed the entire config object.

¶Getting a section

Sections are retrieved from the main config object by name:

$database = $config->getSection("database");

If the section does not exist, null is returned.

¶Reading values from a section

Once we have a section, individual keys can be accessed without dot notation.

$host = $database?->get("host");
$port = $database?->getInt("port");

Like Config, each section also supports typed getters from PHP.GT/TypeSafeGetter.

¶Checking whether a key exists

Sometimes null is a valid outcome from get(), so it is useful to check explicitly whether a key exists.

if($database && $database->contains("password")) {
	// password was defined
}

¶Iterating over keys and values

ConfigSection implements IteratorAggregate, so it can be looped over directly.

foreach($database as $key => $value) {
	echo "$key = $value", PHP_EOL;
}

This is useful when copying a section into another object or displaying configuration for diagnostics.

¶Using array-style access

Sections also implement ArrayAccess, so values can be read using array syntax.

echo $database["host"];

The section remains immutable, so writing or unsetting values using array syntax will throw an exception.

¶Converting to an array

If another API expects a plain array, call asArray().

$databaseConfig = $database?->asArray() ?? [];

This returns the internal key-value data of the section.

¶Creating modified copies

ConfigSection is immutable. To add or replace a value, use with() to create a new section instance.

$newDatabase = $database->with("port", "3307");

The original section is unchanged, and the returned section contains the updated value.

This immutability is what allows Config::withMerge() to build combined configurations without mutating earlier objects.

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Once we know how to read configuration, the final piece is Generating config files.