Compare two vectors
<p>I need to compare to columns of data frame in order to find those rows which value in <code>column 2</code> is less than value in <code>column 1</code> by more than or equal to 8. </p>

<p>For example,</p>

<pre><code>DF
V1   V2
10   2
20   29
30   21
40   60
</code></pre>

<p>The output, I would like to have is <code>3rd column</code> of zeros and ones:</p>

<pre><code>DF
    V1   V2  V3
    10   2   1
    20   29  0
    30   21  1
    40   60  0
</code></pre>

<p>Thank you for any suggestions.</p>