title: How to select a subset of columns from table with list in kdb+/q?
body: <p>Given the following table:</p>
  
  <pre><code>time     | col1  col2  col3  ...
  --------------------------------
  10:53:02 | 89    89    76    ...
  ...
  </code></pre>
  
  <p>How does one select a subset of columns from this table (including the index) referenced by a list of column names i.e. <code>cols:('col1';'col3');</code>
  Whereby the expected result would be:</p>
  
  <pre><code>time     | col1  col3
  ----------------------
  10:53:02 | 89    89   
  ...
  </code></pre>
  
  <p>Thanks</p>