title: How can I drop decimal values in a specific column in R dataframe?
body: <p>I have a dataframe shown below (df &lt;- read_csv("~/data.csv"):</p>
  
  <pre><code>gene_id         a       b
  abc100.12       30      70
  abc101.23       40      80
  abc102.345      50      90
  abc103.4567     60      100
  </code></pre>
  
  <p>I want to make change this dataframe like below:</p>
  
  <pre><code>gene_id         a        b
  abc100         30        70
  abc101         40        80
  abc102         50        90
  abc103         60        100
  </code></pre>
  
  <p>Basically, I want to drop decimal values in gene_id column and keep everything else the same.
  If the original dataframe is df (<code>df &lt;- read_csv("~/data.csv")</code>),
  how can I write a R code so that I have a dataframe shown above?</p>