Working with Drupal commerce entities using entity_metadata_wrapper. Just a bunch of exampled copied from the web or added by me. will keep adding over time. now more then just commerce entities

dc_emw.php

<?php

// Basics
// Get a value.
$value = $wrapper->field_x->value();
// If the field is a reference field you will get the field object
// To get the wrapper back use:
$wrapper_b = $wrapper->field_ref;

// To set a value.
$wrapper->field_x = $value;
// Or
$wrapper->field_x->set($value);

// To save the entity
$wrapper->save();

// order.

$order_wrapper = entity_metadata_wrapper('commerce_order', $order);

// Order id.
$order_id = order_wrapper->order_id->value();

// Order Number.
$order_id = order_wrapper->order_number->value();

// User detils.
$uid = $order->uid;
$email = $order->mail;


    $user = user_load_by_mail($email);
    if ($user) {
      $u_wrapper = entity_metadata_wrapper('user', $user);
      $u_wrapper->field_xxx = $x;	    
      $u_wrapper->save();	    
    }


// order total object
$order_total_obj = $order_wrapper->commerce_order_total->value();
// Order total (cents).
$order_total = $order_total_obj['amount'];

// order currency code & amount from wrapper
$currency_code = $order_wrapper->commerce_order_total->currency_code->value();
$order_total = $order_wrapper->commerce_order_total->amount->value();
// Get as a decimal value
$price_decimal = commerce_currency_amount_to_decimal($order_total, $currency_code);



// subtotal without vat
$total_ex_vat = commerce_price_component_total($order_total , 'base_price');

// total tax (in this case vat 20%)
$total_vat = commerce_price_component_total($order_total , 'tax|vat_20');

// subtotal with vat
$sub_total = $total_ex_vat['amount'] + $total_vat['amount'];

// formatted price string with currency sign
$sub_total = commerce_currency_format($sub_total, $currency_code);

// Order state 
$order_status = commerce_order_status_load($order->status);  
$order_state = $order_status['state'];
if ($order_state != 'cart') {
  	....
}

// Get the customer billing profile (this is not the wrapper object for the wrapper object don't use the ->value())
$customer_billing = $order_wrapper->commerce_customer_billing->value();
// Make sure it exists
if (isset($customer_billing)) {
  // Get the customer billing profile wrapper	
  $customer_billing_wrapper = $order_wrapper->commerce_customer_billing;
  // Get the address
  $address = $customer_billing_wrapper->commerce_customer_address->value();  
  // Get organisation name if available.
  if (isset($address['organisation_name'])) {
    $organisation_name = $address['organisation_name'];
  }

  // Format the address.
  $handlers = array('address' => 'address');
  $context = array('mode' => 'render');
  $address_render_array = addressfield_generate($address, $handlers, $context);
  $output = drupal_render($address_render_array);
	
  // Format the address with full name (more compact code) note: $context defaults to render.
  $address_name_array = addressfield_generate($address, array('address' => 'name-oneline'));
  $address_array = addressfield_generate($address, array('address' => 'address'));
  $output = drupal_render($address_name_array);
  $output .= drupal_render($address_array);
	
}	


// Line item


$line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);

// get all line item wrappers from order wrapper
foreach ($order_wrapper->commerce_line_items as $line_item_wrapper) {
  // line item type
  $line_item_type = $line_item_wrapper->type->value();
  // line item type using the bundle.
  $line_item_type = $line_item_wrapper->getBundle();

  // Line Item ID
  $line_id = $line_item_wrapper->getIdentifier();
	
  // check if a product.
  if (in_array($line_item_type, commerce_product_line_item_types())) {

    // line item title
    $line_item_title = $line_item_wrapper->commerce_product->title->value();

    // line item unit price
    $line_item_unit_price = $line_item_wrapper->commerce_unit_price->amount->value();

    // line item formatted unit price
    $line_item_unit_price = commerce_currency_format($line_item_unit_price, $currency_code);

    // line item quantity
    $line_item_quantity = (float)$line_item_wrapper->quantity->value();

    // line item total price
    $line_item_total_price = $line_item_wrapper->commerce_total->amount->value();

    // line item formatted total price
    $line_iten_total_price = commerce_currency_format($line_item_total_price, $currency_code);

    // Product
    
    // Product ID - You can get the product id from its property.    
    $product_id = $line_item_wrapper->commerce_product->product_id->value();
    // But its better prectice to use getIdentifier()
    $product_id = $line_item_wrapper->commerce_product->getIdentifier();
	  
    
    // Product SKU.    
    $sku = $line_item_wrapper->commerce_product->sku->value();

    // Product image	 
    $line_item_wrapper->commerce_product->field_product_image->value();
	 
	  // Load the product.
	  $product = commerce_product_load($product_id);
    

  } else {
    // for shipping & discount line items

    // shipping/discount price
    $line_item_price = $line_item_wrapper->commerce_unit_price->amount->value();

    // shipping/discount formatted price
    $line_item_price = commerce_currency_format($line_item_price, $currency_code);

    // line item TYPE display title
    $line_ite_type_title = commerce_line_item_type_get_name($line_item_wrapper->type->value());

    // for shipping line items
    if ($line_item_wrapper->type->value() == "shipping") {

      // shipping data
      $shipping_data = $line_item_wrapper->value()->data;

      // shipping method display title
      $line_item_title = $shipping_data['shipping_service']['title'];
     // total price
     $line_item_price = $line_item_wrapper->commerce_total->amount->value();

    }

    if ($line_item_wrapper->type->value() == 'commerce_discount') {
      // for discount line items

      // get discount display title (I suspect there might be a better way than this)
      $discount_data = $line_item_wrapper->commerce_unit_price->data->value();
      foreach ($discount_data['components'] as $key => $component) {
        if (!empty($component['price']['data']['discount_component_title'])) {
          $line_item_title = $component['price']['data']['discount_component_title'];
        }
      }
    }
  }
}

// Create a line item / Add product to cart programmatically
commerce_cart_product_add_by_id($product_id, $quantity);



// Product.
$product_wrapper = entity_metadata_wrapper('commerce_product', $product);

// Product Price.
$price_amount = $product_wrapper>commerce_price->amount->value();
$product_wrapper>commerce_price->amount->set($new_price);   

// Stock	
$product_wrapper->commerce_stock_override->value()
$product_wrapper->commerce_stock->value()

  // Create a new product
  $wrapper = entity_metadata_wrapper('commerce_product', commerce_product_new('product'));
  $wrapper->title = $title;
  $wrapper->sku = $sku;
  // Set the price.
  $wrapper->commerce_price->amount = $price;
  $wrapper->commerce_price->currency_code = 'GBP';
  // or $wrapper->commerce_price->amount->set($price);
  // Set the new stock level.
  $wrapper->commerce_stock->set($new_stock);
	
   // Vat & tax
   $p = 1234   // 12.34
   $p = $p * (1 + VAT_RATE); // Add VAT. VAT_RATE a predifined value: define('VAT_RATE', 0.2); 
   $p = commerce_round(COMMERCE_ROUND_HALF_DOWN, $p); // Use commerce round function

	
// Taxonomy – term referenced
// Get the term object.
$term = $product_wrapper->field_availability->value();
// Get the taxonomy term name
$term_name = term->name;
// One liner of the above.
$term_name = $product_wrapper->field_availability->value()->name;

// Taxonomy – term referenced using a term wrapper
$term_wrapper = $product_w->field_availability;
$term_name = $term_wrapper->name->value());

// Read multi value term reference fields.
$terms_wrapper = $product_w->field_availability;
foreach ($term_wrapper as $term) {
  $ex_list[$term->tid] = $term->name;
}
// Write (add) a single multi value field
$x_wrapper->x_field[] = $new_value;
// Write (update second value) a single multi value field
$x_wrapper->x_field[1] = $new_value;
// Write (overwrite all values) a single multi value field
$new_list = array(
  0 => $value1,
  1 => $value2,
);
$x_wrapper->x_field = $new_list;
// Clear multi value field
$x_wrapper->x_field->set();
// or:
$x_wrapper->x_field = array();

// Get the user from a line item
  $order = commerce_order_load($line_item->order_id);
  $order_wrapper = entity_metadata_wrapper('commerce_order', $order);
  $uid = $order_wrapper->uid->value();
  
// Change the order number.
function custmodule_commerce_order_presave($order) {
  $order_wrapper = entity_metadata_wrapper('commerce_order', $order);
  if (isset($order->order_id)) {
     if ($x) {
      $order->order_number = sprintf('%d_x', $order->order_id); 
     }
     else {
       $order->order_number = $order->order_id); 
     }
  }
}

// Other (not D commerce)

// Create a field collection item and set its fields using the entity_metadata_wrapper
// Working on $node field name: field_my_field.
        // Create the field_collection item entity.
        $fc_entity = entity_create('field_collection_item', array('field_name' => 'field_my_field'));
        // Attach the field_collection item entity to the  node.
        $fc_entity->setHostEntity('node', $node);
        // Use an entity_metadata_wrapper.
        $fc_wrapper = entity_metadata_wrapper('field_collection_item', $fc_entity);
        // Set the fields.
        $fc_wrapper->field1 = $field1;
        $fc_wrapper->field2 = $field2;
        // Save.
        $fc_wrapper->save();


// entity reference (not using emw) both the below are the same.
      $entity['field_xx'][LANGUAGE_NONE][0]['target_id'] = $x;
      $entity['field_xx'][LANGUAGE_NONE][0] = array('target_id' => $x, 'target_type' => 'node');

// Using emw	
        $e_wrapper->field_user_ldl_account->set($account_id);

Took an hour of Googling to find the answer on how to reference an EMW value() when it's an array - you had the answer I was looking for with your $price_amount example on line 146! I knew there was a way, thanks!

thanks for this tax EMW insights. have been stuck for days.

Thank you so much for this! I spent way too much time yesterday poking at EntityFieldQuery and EntityMetadataWrapper configurations to try to get order subtotal data. I wish this page had come up much higher in my Google searches at the time!