<p><div><div><div><div data-width="100" data-show-faces="false" data-send="true" data-layout="button_count" data-height="21" data-href="https://www.r-bloggers.com/applying-functions-to-lists-exercises/"></div></div><div><a data-url="https://www.r-bloggers.com/applying-functions-to-lists-exercises/" data-counturl="https://www.r-bloggers.com/applying-functions-to-lists-exercises/" data-count="horizontal" data-text="Applying Functions To Lists Exercises" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
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(This article was first published on <strong><a href="http://r-exercises.com/2016/09/19/applying-functions-to-lists/"> R-exercises</a></strong>, and kindly contributed to <a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers)</a> </div>
<p><a target="_blank" href="http://r-exercises.com/wp-content/uploads/2016/09/checklist-1622517_960_720.png?cfa4f2"><img sizes="(max-width: 250px) 100vw, 250px" alt="checklist-1622517_960_720" class="wp-image-2003" src="https://i0.wp.com/r-exercises.com/wp-content/uploads/2016/09/checklist-1622517_960_720-300x300.png?resize=250%2C250" data-recalc-dims="1"></a>The <code>lapply()</code> function applies a function to individual values of a list, and is a faster alternative to writing loops.</p>
<p>Structure of the <code>lapply()</code> function:<br>
<code>lapply(LIST, FUNCTION, ...)</code></p>
<p>The list variable used for these exercises:<br>
<code>list1 &lt;- list(observationA = c(1:5, 7:3), observationB=matrix(1:6, nrow=2))</code></p>
<p>Answers to the exercises are available <a target="_blank" href="http://r-exercises.com/2016/9/19/applying-functions-to-lists-solutions/">here</a>.</p>
<p><strong>Exercise 1</strong></p>
<p>Using <code>lapply()</code>, find the length of <code>list1</code>‘s observations.</p>
<p><strong>Exercise 2</strong></p>
<p>Using <code>lapply()</code>, find the sums of <code>list1</code>‘s observations.</p>
<p><strong>Exercise 3</strong></p>
<p>Use <code>lapply()</code> to find the quantiles of <code>list1</code>.</p>
<p><strong>Exercise 4</strong></p>
<p>Find the classes of <code>list1</code>‘s sub-variables, with <code>lapply()</code>.</p>
<p><strong>Exercise 5</strong></p>
<p>Required function:<br>
<code>DerivativeFunction &lt;- function(x) { log10(x) + 1 }</code></p>
<p>Apply the “<code>DerivativeFunction</code>” to <code>list1</code>.</p>
<p><strong>Exercise 6</strong></p>
<p>Script the “<code>DerivativeFunction</code>” within <code>lapply()</code>. The dataset is <code>list1</code>.</p>
<p><strong>Exercise 7</strong></p>
<p>Find the unique values in <code>list1</code>.</p>
<p><strong>Exercise 8</strong></p>
<p>Find the range of <code>list1</code>.</p>
<p><strong>Exercise 9</strong></p>
<p>Print <code>list1</code> with the <code>lapply()</code> function.</p>
<p><strong>Exercise 10</strong></p>
<p>Convert the output of Exercise 9 to a vector, using the <code>unlist()</code>, and <code>lapply()</code>, functions.</p>
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