title: How to define column that doesn't have NAs in sequence of certain rows?
body: <p>Here is some sample data:</p>
  <pre><code>    df1 &lt;- read.table(text = &quot;Date  Client1 Client2 Client3
                    01.01.2019    0   0   2
                    01.02.2019    0   0   3
                    01.03.2019    0   0   4
                    01.04.2019    0   0   4
                    01.05.2019    0   0   4
                    01.06.2019    1   0   4
                    01.07.2019    0   0   0
                    01.08.2019    0   0   1
                    01.09.2019    0   0   0
                    01.10.2019    0   3   0
                    01.11.2019    0   0   2
                    01.12.2019    2   0   0
                    01.01.2020    3   4   3
                    01.02.2020    4   0   3
                    01.03.2020    5   0   0
                    01.04.2020    5   0   0
                    &quot;, header = TRUE)
  df1[df1 == 0] &lt;- NA
  </code></pre>
  <p>And the question is how to find a logical index for every column that contains a sequence of 5 or more rows that doesn't contains NAs.</p>
  <pre><code>Client1 TRUE
  Client2 FALSE
  Client3 TRUE
  </code></pre>