title: week number and year combination
body: <p>Several questions have been asked in the past on Weeknumber and Year in Excel, however, I have a specific question that I couldn't find the answer to.</p>
  
  <p>I'm trying to get a combination of year and week number in the format of YYWW, so for example 1752, or 1801, based on a column with dates, something like this:</p>
  
  <pre><code>Date         Year  Week
  01-01-2018   18    01
  02-01-2018   18    01
  ...
  31-12-2018   18    01
  </code></pre>
  
  <p>Year is simply determined by using the <code>YEAR</code> function on the date, and the week number is determined using the <code>ISOWEEKNUM</code> function on the date.
  This is then followed by some further processing, summing data based on year and week number, and the  issue is that then also the data of the 31st of December 2018 is taken into account for week 1 of 2018, while the 31st of December is obviously not in week 1 of 2018, but in week 1 of 2019.</p>
  
  <p>So the question is, how could I "fix" this, so how can I get Excel to give me 19 &amp; 01 for 31-12-2018? Ideally I am looking for a solution that does not involve any VBA.</p>
  
  <p>Any help is much appreciated!</p>