understand callback function in wordpress - wordpress

Question

I'd like to understand what $args['id'] mean in the add_settings_section() callback function, and how the loop get the id of every section:
here my array to add sections information:
$ap_sections = [
'section-theme-settings' => [
'title' => 'Theme settings',
'desc' => 'General theme settings'
],
'section-styling-settings' => [
'title' => 'Styling settings',
'desc' => 'settings for editing colors, fonts and css.'
],
'section-social-settings' => [
'title' => 'Social settings',
'desc' => 'Edit your social media profiles.'
]
];
here my loop:
foreach ( $ap_sections as $section_id => $section_value ) {
add_settings_section( $section_id, $section_value['title'], 'ap_render_section', 'ap-theme-options' );
}
and here ap_render_section callback function:
function ap_render_section($args) {
global $ap_sections;
echo '<p>' . $ap_sections[ $args['id'] ] ['desc'] . '</p>';
echo '<hr />';
}
my goal is understand not copy and pate code

Answer 1

Each section should have unique ID. And first parameter in add_settings_section function is ID of that added section.
Check the code from WP Codex:
add_settings_section(
'eg_setting_section',
'Example settings section in reading',
'eg_setting_section_callback_function',
'reading'
);
function eg_setting_section_callback_function( $arg ) {
// echo section intro text here
echo '<p>id: ' . $arg['id'] . '</p>'; // id: eg_setting_section
echo '<p>title: ' . $arg['title'] . '</p>'; // title: Example settings section in reading
echo '<p>callback: ' . $arg['callback'] . '</p>'; // callback: eg_setting_section_callback_function
}
As you can see, $arg['id'] here is "eg_setting_section".
So, add_settings_section function passes your added unique slug and title to callback function as array elements.