t;            &lt;list&gt;               
## 1 &lt;split [2.2K/732]&gt; train/test split &lt;tibble [2,198 √ó 81]&gt;
```

<div class="countdown" id="timer_5e46e385" style="right:0;bottom:0;" data-warnwhen="0">
<code class="countdown-time"><span class="countdown-digits minutes">01</span><span class="countdown-digits colon">:</span><span class="countdown-digits seconds">00</span></code>
</div>

---

```r
simple_split %&gt;% 
  mutate(train_set = map(splits, training))
## # # Monte Carlo cross-validation (