'>c</a></span>(<span class='fl'>NA</span> , <span class='fl'>NA</span> , <span class='fl'>1</span> , <span class='fl'>2</span> , <span class='fl'>3</span> , <span class='fl'>NA</span>)
)

<span class='no'>DF2</span> <span class='kw'>&lt;-</span> <span class='fu'><a href='https://www.rdocumentation.org/packages/base/topics/data.frame'>data.frame</a></span>(
    <span class='kw'>id</span> <span class='kw'>=</span> <span class='fu'><a href='https://www.rdocumentation.org/packages/base/topics/c'>c</a></span>(<s