joining strings in a table according to values in another column : <p>I got a table like this:</p>

<pre><code>id     words
1     I like school.
2     I hate school.
3     I like cakes.
1     I like cats.
</code></pre>

<p>Here's what I want to do, joining the strings in each row according to id. </p>

<pre><code>id    words
1    I like school. I like cats.
2    I hate school.
3    I like cakes.
</code></pre>

<p>Is there a package to do that in R?</p>
