title: "Warning: too many (few) values" for using tidyr packages in R
body: <p>I have the following data set <code>D7</code></p>
  
  <pre><code>name sex_age eye_color height
  1    J    M.34     Other     61
  2    A    F.55      Blue     59
  3    T    M.76     Brown     51
  4    D    F.19     Other     57
  </code></pre>
  
  <p>I want to separate the column <code>sex_age</code> into <code>sex</code> column and <code>age</code> column, so I type</p>
  
  <pre><code>separate(D7,sex_age,c('sex','age'),sep='.')
  </code></pre>
  
  <p>But it generates</p>
  
  <pre><code>name sex age eye_color height
  1    J             Other     61
  2    A              Blue     59
  3    T             Brown     51
  4    D             Other     57
  Warning message:
  Too many values at 4 locations: 1, 2, 3, 4 
  </code></pre>
  
  <p>Also, when I modify my original data set <code>D7</code> into <code>D8</code></p>
  
  <pre><code>name sex_age eye_color height
  1    J    M_34     Other     61
  2    A    F_55      Blue     59
  3    T    M_76     Brown     51
  4    D    F_19     Other     57
  </code></pre>
  
  <p>And I type <code>D7 %&gt;% separate(sex_age,c('sex','age'),sep="_")</code> it gives</p>
  
  <pre><code>name  sex  age eye_color height
  1    J M.34 &lt;NA&gt;     Other     61
  2    A F.55 &lt;NA&gt;      Blue     59
  3    T M.76 &lt;NA&gt;     Brown     51
  4    D F.19 &lt;NA&gt;     Other     57
  Warning message:
  Too few values at 4 locations: 1, 2, 3, 4 
  </code></pre>
  
  <p>Did I misuse the <code>separate</code> function? I am very puzzled. Thank you for any suggestions.</p>