title: python: how to get strings before decimal point?
body: <p>I have a pandas data frame, df, which looks like this:</p>
  
  <pre><code>ENSGid              IB-7645        FB-AAPZ      FB-AAQ1      2J-AABH
  ENSG00000242268.2   3593.368439    2147.028513  0            2586.98327
  ENSG00000270112.3   0              0            104.0612396  89.73803605
  ENSG00000167578.15  48710.20691    80149.55054  84261.08439  114534.9553
  ENSG00000273842.1   0              0            0            0
  ENSG00000078237.5   99587.29996    91523.92632  91066.1147   72151.84485
  ENSG00000146083.10  247691.6483    350932.9484  254480.9342  374328.7091
  </code></pre>
  
  <p>How can I remove the decimal point and numbers after them so that the data frame looks like this:</p>
  
  <pre><code>    ENSGid              IB-7645        FB-AAPZ      FB-AAQ1      2J-AABH
      ENSG00000242268     3593.368439    2147.028513  0            2586.98327
      ENSG00000270112     0              0            104.0612396  89.73803605
      ENSG00000167578     48710.20691    80149.55054  84261.08439  114534.9553
      ENSG00000273842     0              0            0            0
      ENSG00000078237     99587.29996    91523.92632  91066.1147   72151.84485
      ENSG00000146083     247691.6483    350932.9484  254480.9342  374328.7091
  </code></pre>
  
  <p>I have read the pandas cookbook and searched answers in the stackoverflow, but all the answers are for float to integer but not for string.</p>
  
  <p>All help greatly appreciated.</p>