title: How to drop rows from pandas data frame that contains a particular string in a particular column?
body: <p>I have a very large data frame in python and I want to drop all rows that have a particular string inside a particular column.</p>
  
  <p>For example, I want to drop all rows which have the string "XYZ" as a substring in the column C of the data frame.</p>
  
  <p>Can this be implemented in an efficient way using .drop() method?</p>