<i>Time complexity: O(1)</i><blockquote>Add the <i>string</i> value to the head (LPUSH) or tail (RPUSH) of the liststored at <i>key</i>. If the key does not exist an empty list is created just beforethe append operation. If the key exists but is not a List an erroris returned.</blockquote>
<h2><aname="Return value">Return value</a></h2><ahref="ReplyTypes.html">Integer reply</a>, specifically, the number of elements inside the list after the push operation.