Appending to array in a for loop?

<p>I&#39;ve got the following code:</p> <pre><code>for _, e := range events { //Get all the items for this event. items, err := getBidItemsForEvent(e.Event.Event_ID) fmt.Printf(&#34;%#v\n\n&#34;, items) if err != nil { fmt.Println(&#34;Error at getting item events in GetEventsByUserId&#34;, err.Error()) } //Append them to the events items array. for _, i := range items { e.Items = append(e.Items, i) fmt.Println(i) } } </code></pre> <p>The idea is there&#39;s multiple events with multiple items going in to them. Within the events loop, I get the items from the event. The printf items prints these out (an array of items). The next for loop is supposed to append the item to the original event items array. I can also see the item by printing &#39;i&#39;.</p> <p>What&#39;s returned is a nil array though. Am I missing something on how to append within a for loop?</p> <hr/>**评论：**<br/><br/>natdm: <pre><p>Aha! Solved it..</p> <p>I have to append directly to the slice, not within the for loop.</p> <pre><code>for i, event := range events { //Get all the items for this event. items, err := getBidItemsForEvent(event.Event.Event_ID) fmt.Printf(&#34;%#v\n\n&#34;, items) if err != nil { fmt.Println(&#34;Error at getting item events in GetEventsByUserId&#34;, err.Error()) } //Append them to the events items array. for _, item := range items { events[i].Items = append(events[i].Items, item) } } </code></pre></pre>dchapes: <pre><p>This:</p> <pre><code>for _, item := range items { events[i].Items = append(events[i].Items, item) } </code></pre> <p>is better written as:</p> <pre><code>events[i].Items = append(events[i].Items, items...) </code></pre></pre>natdm: <pre><p>Nice, I didn&#39;t know about that. Thanks!</p></pre>Fwippy: <pre><p><code>e</code> is a copy of the event.</p> <p>Compare: <a href="https://play.golang.org/p/OMdDdz1K32" rel="nofollow">https://play.golang.org/p/OMdDdz1K32</a> (similar to yours) vs <a href="https://play.golang.org/p/ireemFw2Xi" rel="nofollow">https://play.golang.org/p/ireemFw2Xi</a></p></pre>justinisrael: <pre><p>If events were a slice of Event pointers, then I would think it would work fine. If your slice contains value types, then they are copies on each loop and don&#39;t retain your changes when assigning to the Items field </p></pre>