Hi, If you have one row per day of the year, you can find out easily where the row corresponding to "TODAY()-1" is located by finding out the number of days between Jan 1st of that year and "yesterday". This would be something like (you may need to adjust based on the heading of your column(s)):
=DAYS(YEAR(TODAY()-1)-1;MONTH(TODAY()-1);DAY(TODAY()-1);YEAR(TODAY()- 1)-1;1;1) The formula above calculates the number of days between yesterday last year and Jan 1st of last year. Now, you need to find in which column to add. Since you seem to have a heading providing the year, you can use the MATCH() function to locate the column: =MATCH(YEAR(TODAY()-1)-1;$a$1:$z$1;0) This should give you the column where last year's data is located (I used a1 to z1, but any row reference will work). To add the values, you now just need to use a combination of SUM() and OFFSET(): =SUM(OFFSET($A$2;0;MATCH(YEAR(TODAY()-1)-1;$a$1:$z$1;0)- 1;DAYS(YEAR(TODAY()-1)-1;MONTH(TODAY()-1);DAY(TODAY()-1);YEAR(TODAY()- 1)-1;1;1);1)) What that does: OFFSET() allows you to create dynamic arrays for functions like SUM(). I used the anchor point $A$2 (I supposed your heading is in row 1), and told OFFSET to move from that reference 0 rows down and "MATCH(YEAR(TODAY()-1)-1;$a$1:$z$1;0)-1" columns to the right; then, from that new point, make an array that is "DAYS(YEAR(TODAY()-1)- 1;MONTH(TODAY()-1);DAY(TODAY()-1);YEAR(TODAY()-1)-1;1;1)" rows high and 1 column wide. The resulting array is then used by SUM() to calculate the total rainfall. This will probably need to be adjusted a bit to take into account the position of your column heading and to correctly find the row where to stop, but you should now have something to play with. I hope this helps. Rémy Gauthier. Le dimanche 07 mai 2017 à 21:55 +0200, Hylton Conacher (ZR1HPC) a écrit : > Hi, > > > I have a spreadsheet I use to draw graphs and extract information about > the rainfall in my area for the last two years. > > I need to create a formula that will count how many days it rained > > between the start of the year, both last year and this year, so I can > > compare the amount of rainfall that was received during that time frame. > > > The example below is a sample dataset that shows how much rainfall was > received in 2016 or 2017, on each of the four days > > Example: > > > > Month Day 2016 2017 > > > > Jan 1 0 15 > > > > Feb 29 1 0 > > > > May 6 0 1 > > > > Sept 22 15 5 > > > From this we can determine that 16mm of rain fell in 2016 over 2 days. > > Likewise we can determine that 21mm of rain fell in 2017 but over 3 days. > > > Today is the 7th of May 2017 and I would like a formula to work out how > > many days the rainfall received between(and incl) 2016/01/01 and the day > before TODAY last year. The answer for 2016 is 1 i.e. it only rained > > once between the dates specified, however the answer for 2017 is 16 as > it rained twice between TODAY-1 and 2017/1/1. I had thought of using > > COUNTIF or DAYS or =COUNTIF(C2:SUM(TODAY()-1,">0")), however the problem > is that I do not have a single date column, but three. > > > This formula will allow me to create a graph showing how much rainfall > > had fallen last year compared to this year between the beginning of the > year(01/01) and the day prior to Today. > > I had thought of converting the first two columns into a single and > > having the text name of the month with each successive line being a new > > date in that month until the month changed, however I was unable to get > > it to work i.e. automatically change month after 31 days in January to > read February 01. > > As you can imagine I have 367 rows of data per year, mostly with 0 as a > value, however there are odd days it does rain. > > > Any comments, and if you want the original spreadsheet, just yell where > to put it i.e. Nabble etc. > > Regards > Hylton > -- To unsubscribe e-mail to: users+unsubscr...@global.libreoffice.org Problems? http://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette List archive: http://listarchives.libreoffice.org/global/users/ All messages sent to this list will be publicly archived and cannot be deleted
