n class="op">(</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> NULL</span>
<span class="r-in"><span><span class="fu"><a href="peek.html">peek</a></span><span class="op">(</span><span class="fu">deque</span><span class="op">(</span><span class="op">)</span>, default <span class="op">=</span> <span class="fl">0</span><span class="op">)</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] 0</span>
<span cla