title: How to echo custom woocommerce product variation field?
body: <p>I've added a custom field for each woocommerce product variation.</p>
  
  <p>I've added a datetime input field. Then I will need to auto delete the variation when the datetime value is already past. So auto expire the woocommerce product variation.</p>
  
  <p>This is my code for adding the custom input field.</p>
  
  <pre><code>// Add Variation Settings
  add_action( 'woocommerce_product_after_variable_attributes', 'variation_settings_fields', 10, 3 );
  
  // Save Variation Settings
  add_action( 'woocommerce_save_product_variation', 'save_variation_settings_fields', 10, 2 );
  
  //Create New fields for Variations
  function variation_settings_fields( $loop, $variation_data, $variation ) {
      // Text Field
      woocommerce_wp_text_input( 
          array( 
              'id'          =&gt; '_text_field_date_expire[' . $variation-&gt;ID . ']',
              'class'       =&gt; '_text_field_date_expire',
              'type'        =&gt; 'datetime-local',  
              'label'       =&gt; __( 'Date of Expiration', 'woocommerce' ), 
              'placeholder' =&gt; '',
              'desc_tip'    =&gt; 'true',
              'description' =&gt; __( 'Expiration of Each Product Variation', 'woocommerce' ),
              'value'       =&gt; get_post_meta( $variation-&gt;ID, '_text_field_date_expire', true )
          )
      );
  }
  
  
  //Save New Fields for Variation
  function save_variation_settings_fields( $post_id ) {
      // Text Field
      $text_field = $_POST['_text_field_date_expire'][ $post_id ];
      if( ! empty( $text_field ) ) {
          update_post_meta( $post_id, '_text_field_date_expire', esc_attr( $text_field ) );
      }
  }
  </code></pre>
  
  <p>How could I get the input field value per each variations and echo it, so I could use the value for another function and delete the variations automatically?</p>