title: How to make a new column using 2 criteria
body: <p>I am trying to make a column showing the financial year of a date in r studio.</p>
  <p>I currently have 2 columns, one showing the month (as a number) and one showing the year.</p>
  <p>I would like the third column to display the financial year, by picking out:</p>
  <p>if month &lt;= 3 &amp; year = 2017, then financial year= FY1617</p>
  <p>if month &gt;= 4 &amp; year = 2017, then financial year= FY1718</p>
  <p>etc. etc.</p>
  <p>It seems like this should be a simple thing to do, but I've tried lots of things and can't work it out!</p>