title: spilt columns twice using Python
body: <p>I have a large dataset (4GB) like this:</p>
  <pre><code>            userID   date   timeofday   seq
  0   1000014754    20211028         20  133669542676:1:148;133658378700:1:16;133650937891:1:85
  1   1000019906    20211028          6  508420199:0:0;133669581685:1:19
  2   1000019906    20211028         22  133665269544:0:0 
  </code></pre>
  <p>From this, I would like to split &quot;seq&quot; by &quot;;&quot; first and create a new dataset with renames. It looks like this:</p>
  <pre><code>            userID   date   timeofday   seq1      seq2  seq3 ... seqN
  0   1000014754    20211028         20  133669542676:1:148 133658378700:1:16 133650937891:1:85
  1   1000019906    20211028          6  508420199:0:0 133669581685:1:19 None None
  2   1000019906    20211028         22  133665269544:0:0 None None None
  </code></pre>
  <p>Then I want to split the seq1,seq2,...,seqN by &quot;:&quot;, and create a new dataset with renames. It looks like this:</p>
  <pre><code>            userID   date   timeofday   name1  click1  time1 name2 click2 time2 ....nameN clickN timeN
  0   1000014754    20211028         20  133669542676 1 148 133658378700 1 16 133650937891 1 85 None None None
  1   1000019906    20211028          6  508420199 0 0 133669581685 1 19 None None None None None None
  2   1000019906    20211028         22  133665269544 0 0 None None None None None None None None None
  </code></pre>
  <p>I know pandas.split can split the columns, but I don't know how to split it effficiently. Thank you!</p>