<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/efficient-processing-with-apply-exercises/"></div></div><div><a data-url="https://www.r-bloggers.com/efficient-processing-with-apply-exercises/" data-counturl="https://www.r-bloggers.com/efficient-processing-with-apply-exercises/" data-count="horizontal" data-text="Efficient Processing With Apply() Exercises" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
<div>
(This article was first published on <strong><a href="http://r-exercises.com/2016/09/08/efficient-processing-with-apply-exercises/"> 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="https://i0.wp.com/r-exercises.com/wp-content/uploads/2016/09/Apply-paint.png?resize=205%2C88"><img alt="apply-paint" class="wp-image-1788" src="https://i0.wp.com/r-exercises.com/wp-content/uploads/2016/09/Apply-paint.png?resize=205%2C88" data-recalc-dims="1"></a>The <code>apply()</code> function is an alternative to writing loops, via applying a function to columns, rows, or individual values of an array or matrix.</p>
<p>The structure of the <code>apply()</code> function is:<br>
<code>apply(X, MARGIN, FUN, ...)</code></p>
<p>The matrix variable used for the exercises is:<br>
<code>dataset1 &lt;- cbind(observationA = 16:8, observationB = c(20:19, 6:12))</code></p>
<p>Answers to the exercises are available <a target="_blank" href="http://r-exercises.com/2016/09/08/efficient-processing-with-apply-solutions/">here</a>.</p>
<p><strong>Exercise 1</strong></p>
<p>Using <code>apply()</code>, find the row means of <code>dataset1</code></p>
<p><strong>Exercise 2</strong></p>
<p>Using <code>apply()</code>, find the column sums of <code>dataset1</code></p>
<p><strong>Exercise 3</strong></p>
<p>Use <code>apply()</code> to sort the columns of <code>dataset1</code></p>
<p><strong>Exercise 4</strong></p>
<p>Using <code>apply()</code>, find the product of <code>dataset1</code> rows</p>
<p><strong>Exercise 5</strong></p>
<p>Required function:<br>
<code>DerivativeFunction &lt;- function(x) { log10(x) + 1 }</code></p>
<p>Apply “<code>DerivativeFunction</code>” on the rows of <code>dataset1</code></p>
<p><strong>Exercise 6</strong></p>
<p>Re-script the formula from Exercise 5, in order to define “<code>DerivativeFunction</code>” inside the <code>apply()</code> function</p>
<p><strong>Exercise 7</strong></p>
<p>Round the output of the Exercise 6 formula to 2 places</p>
<p><strong>Exercise 8</strong></p>
<p>Print the columns of <code>dataset1</code> with the <code>apply()</code> function</p>
<p><strong>Exercise 9</strong></p>
<p>Find the length of the <code>dataset1</code> columns</p>
<p><strong>Exercise 10</strong></p>
<p>Use <code>apply()</code> to find the range of numbers<br>
within the <code>dataset1</code> columns</p>
<p><div><div><div><div data-width="55" data-show-faces="false" data-send="true" data-layout="box_count" data-height="62" data-href="https://www.r-bloggers.com/efficient-processing-with-apply-exercises/"></div></div><div><a data-url="https://www.r-bloggers.com/efficient-processing-with-apply-exercises/" data-counturl="https://www.r-bloggers.com/efficient-processing-with-apply-exercises/" data-count="vertical" data-text="Efficient Processing With Apply() Exercises" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
<div>
<div>To <strong>leave a comment</strong> for the author, please follow the link and comment on their blog: <strong><a href="http://r-exercises.com/2016/09/08/efficient-processing-with-apply-exercises/"> R-exercises</a></strong>.</div>
<hr>
<a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers.com</a> offers <strong><a rel="nofollow" href="https://feedburner.google.com/fb/a/mailverify?uri=RBloggers">daily e-mail updates</a></strong> about <a title="The R Project for Statistical Computing" rel="nofollow" href="https://www.r-project.org/">R</a> news and <a title="R tutorials" rel="nofollow" href="https://www.r-bloggers.com/?s=tutorial">tutorials</a> on topics such as: <a title="Data science" rel="nofollow" href="https://www.r-bloggers.com/?s=data%20science">Data science</a>, <a title="Big Data" rel="nofollow" href="https://www.r-bloggers.com/?s=Big%20Data">Big Data, <a title="R jobs" rel="nofollow" href="https://www.r-users.com/">R jobs</a>, visualization (<a title="ggplot and ggplot2 tutorials" rel="nofollow" href="https://www.r-bloggers.com/?s=ggplot2">ggplot2</a>, <a title="Boxplots using lattice and ggplot2 tutorials" rel="nofollow" href="https://www.r-bloggers.com/?s=boxplot">Boxplots</a>, <a title="Maps and gis" rel="nofollow" href="https://www.r-bloggers.com/?s=map">maps</a>, <a title="Animation in R" rel="nofollow" href="https://www.r-bloggers.com/?s=animation">animation</a>), programming (<a title="RStudio IDE for R" rel="nofollow" href="https://www.r-bloggers.com/?s=RStudio">RStudio</a>, <a title="Sweave and literate programming" rel="nofollow" href="https://www.r-bloggers.com/?s=sweave">Sweave</a>, <a title="LaTeX in R" rel="nofollow" href="https://www.r-bloggers.com/?s=LaTeX">LaTeX</a>, <a title="SQL and databases" rel="nofollow" href="https://www.r-bloggers.com/?s=SQL">SQL</a>, <a title="Eclipse IDE for R" rel="nofollow" href="https://www.r-bloggers.com/?s=eclipse">Eclipse</a>, <a title="git and github, Version Control System" rel="nofollow" href="https://www.r-bloggers.com/?s=git">git</a>, <a title="Large data in R using Hadoop" rel="nofollow" href="https://www.r-bloggers.com/?s=hadoop">hadoop</a>, <a title="Web Scraping of google, facebook, yahoo, twitter and more using R" rel="nofollow" href="https://www.r-bloggers.com/?s=Web+Scraping">Web Scraping</a>) statistics (<a title="Regressions and ANOVA analysis tutorials" rel="nofollow" href="https://www.r-bloggers.com/?s=regression">regression</a>, <a title="principal component analysis tutorial" rel="nofollow" href="https://www.r-bloggers.com/?s=PCA">PCA</a>, <a title="Time series" rel="nofollow" href="https://www.r-bloggers.com/?s=time+series">time series</a>, <a title="finance trading" rel="nofollow" href="https://www.r-bloggers.com/?s=trading">trading</a>) and more...
<img height="1" alt="" width="1" src="http://feeds.feedburner.com/~r/RBloggers/~4/nfEpYd2c8js"></a></div>