title: Remove parenthesis from a character string
body: <p>I am trying to remove a parenthesis from a string in R and run into the following error:</p>
  
  <pre><code>string &lt;- "log(M)"
  gsub("log", "", string) # Works just fine
  gsub("log(", "", string) #breaks
  # Error in gsub("log(", "", test) : 
  #   invalid regular expression 'log(', reason 'Missing ')''
  </code></pre>