Get variations IDs from a variable product in Woocommerce 3

Question

It is necessary to get the value from the array with the key [0], but the array is in the object. How can I put it in a variable?

  WC_Product_Variable Object          


        

Answer 1

To get the children variation Ids for a variable product, use WC_product get_children() method (that doesn't have/allow any arguments):

// (if needed) Get an instance of the WC_product object (from a dynamic product ID)
$product = wc_get_product($product_id);

// Get children product variation IDs in an array
$children_ids = $product->get_children();

// Get the first ID value
$children_id = reset($children_ids); 
// or 
$children_id = $children_ids[0];

Tested and works.