Get attributes of child shortcodes in parent.

wordpress_shortcode.php

<?php
// Currently in: Container
$mycontent = "Some content from before";

// Attributes of Elements
$elements = array();

// Register shortcode
add_shortcode('container_element', function($atts, $content) use(&$elements) {
	$atts = shortcode_atts(array(
		'prop1' => 1
	), $atts);
	$atts['content'] = $content;
	array_push($elements, $atts);
});

// Run Shortcodes
do_shortcode($mycontent);

// Do Something with the elements
foreach($elements as $el)
	echo $el['prop1'];