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(This article was first published on <strong><a href="http://r-exercises.com/2016/12/01/scripting-loops-exercises-vol-2/"> R-exercises</a></strong>, and kindly contributed to <a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers)</a> </div>
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<p>[For this exercise, first write down your answer, without using R. Then, check your answer using R.]</p>
<p>Answers to the exercises are available <a target="_blank" rel="nofollow" href="http://r-exercises.com/2016/12/01/scripting-loops-exercises-vol-2-solutions/">here</a>.</p>
<p><strong>Exercise 1</strong></p>
<p>Using the following variables:<br>
<code><br>
x=1<br>
i=c(1:10)<br>
</code><br>
For this exercise, write a for() loop that increments x by two for each i.</p>
<p><strong>Exercise 2</strong><br>
Using the following variables:<br>
<code><br>
x=1<br>
y=40<br>
i=c(1:10)<br>
</code><br>
For this exercise, write a for() loop that increments x by three and decrease y by two, for each i.</p>
<p><strong>Exercise 3</strong><br>
Using the following variables:<br>
<code><br>
a,b<br>
</code><br>
For this exercise, write a nested for() loop (where the outer for loop increment a from 2 to 8 by 1, and the<br>
inner for loop increment b from 1 to 6 by 1) that print “a, ‘ less than ‘,b” if a&lt;b.</p>
<p><strong>Exercise 4</strong><br>
Using the following variable:<br>
<code><br>
x=c(2,4)<br>
</code><br>
For this exercise, type a while () loop that adds even numbers to x, while the length of x is less than 12.<br>
For example, in the first iteration you get <code>x = 2,4,6</code>, and the third <code>x =2,4,6,8</code>.</p>
<p><strong>Exercise 5</strong></p>
<p>Using the following variable:<br>
<code><br>
a=15:10<br>
b=20:15<br>
</code><br>
For this exercise, type a while () loop that computes a vector<code> x=225 224 221 216 209 200</code> ,such that </p>
<p><code><br>
x[1]=a[1]*b[6]<br>
x[2]=a[2]*b[5]<br>
x[3]=a[3]*b[5]<br>
.<br>
.<br>
x[6]=a[6]*b[1]
<p></p>
<p><strong>Exercise 6</strong></p>
<p>Using the following variable:<br>
<code><br>
a=1:10<br>
</code><br>
For this exercise, type a while () loop that computes a vector<code> x=1  3  6 10 15 21 28 36 45 55</code> ,such that<br>
<code><br>
 x[1]=a[1]<br>
 x[2]=a[1]+a[2]<br>
 x[3]=a[1]+a[2]+a[3]<br>
 .<br>
 .<br>
</code></p>
<p><strong>Exercise 7</strong></p>
<p>Using the following variable:<br>
<code><br>
i=10<br>
x=10<br>
</code><br>
For this exercise, type a repeat () loop that decreasing i computes <code>x=x/i</code> until <code>i=0</code>.</p>
<p><strong>Exercise 8</strong></p>
<p>Using the following variable:<br>
<code><br>
x=100<br>
y=50<br>
i=1<br>
</code><br>
For this exercise, type a repeat () loop that incrementing i computes <code>x=x-i and y=y+i</code> until <code>x&lt;y</code>.</p>
<p><strong>Exercise 9</strong></p>
<p>Using the following variable:<br>
<code><br>
x=as.Date(&quot;10/11/2017&quot;,&quot;%d/%m/%Y&quot;)<br>
</code><br>
For this exercise, type a repeat () loop that increment x until x is equal to 31/12/2017.</p>
<p><strong>Exercise 10</strong></p>
<p>Using the following variable:</p>
<p><code><br>
x=cbind(c(1,2,3,4,9,7,4,3),c(3,1,2,5,3,6,5,3))<br>
</code></p>
<p>For this exercise, type a for() loop that calculate <code>y=3   8  18  44 126 140 100  84</code>, such that<br>
<code><br>
y[1]=x[1,1]*x[1,2]<br>
y[2]=x[2,1]*sum(x[1:2,2])<br>
y[3]=x[3,1]*sum(x[1:3,2])<br>
.<br>
.<br>
.<br>
y[8]=x[8,1]*sum(x[1:8,2])<br>
</code></p>
<p><strong>Want to practice loops a bit more? We have more exercise sets on this topic <a target="_blank" rel="nofollow" href="http://r-exercises.com/tag/loops">here</a>.</strong></p>

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