How to Calculate Age from Year Only in Google Sheets - google-sheets

I have the year a car was purchased in column A. For example, 2015. I'm trying to calculate the age of the vehicle comparing the year provided in column A to TODAY() in an arrayformula, like this...
={"Vehicle Age";arrayformula(if(A2:A="",,(datedif(A2:A,today(),"Y"))))}
For some reason, it gives me the number 115 as the result for every cell where a year has been specified. Any idea why? I can't seem to find an answer on this anywhere on the internets.
Thanks for your help!

You are mixing apples and oranges here, so to speak.
Internally, Google Sheets sees all full dates as a number of days from an origin point of December 31, 1899. As such, the year 2015 on its own, in a comparison with a full date will be seen as two-thousand-fifteen days since December 31, 1899 (or July 7, 1905 — which was 115 some-odd years ago, as would be the case with any relatively recent year, because they'll all be interpreted in their raw form by Sheets as a cluster of days from late June to early July of 1905).
Instead, you want to compare the years only, which will mean extracting the year from TODAY(), since A2:A are already year-only numbers:
={"Vehicle Age";arrayformula(if(A2:A="",,year(TODAY())-A2:A))}
However, since any year's car models are actually released the year before, you may want to add a year to your formula:
={"Vehicle Age";arrayformula(if(A2:A="",,year((TODAY())-A2:A)+1))}
Of course, you could also have turned your A2:A years into real dates (e.g., January 1 of each year listed) and then used datedif as well:
={"Vehicle Age";arrayformula(if(A2:A="",,datedif(DATE(A2:A,1,1),today(),"Y")))}
... or with that extra year added ...
={"Vehicle Age";arrayformula(if(A2:A="",,datedif(DATE(A2:A,1,1),today(),"Y")+1))}

={"Vehicle Age";arrayformula(if(A2:A="",,datedif(DATE(A2:A,1,1),today(),"Y")))}
Not working

Related

Is December somehow special in Google Sheets?

I count the number of transactions made per month
=if(COUNTIF(ArrayFormula(month(
indirect($H$12&"!$F$3:F")
)),10)
=0,"",COUNTIF(ArrayFormula(month(
indirect($H$12&"!$F$3:F")
)),10)
)
Where 10 is October, while referencing a sheet named in $H$12. This works well for months 1-11.
When it comes to December, I am getting a seemingly random (wrong) integer back.
Is December somehow special?
I ended up using Filter. Seems to work perfectly fine
=COUNTA(filter(indirect($H$12&"!$A$3:A"),month(indirect($H$12&"!$F$3:F"))=10))

Select a "tax month" with a non standard month start/end

I have a Google Sheet with data like this:
Date
In
Out
July 13
£40
July 21
£60
etc.
I'd like to add another column "month" which specifies what month the entry was made in. Only problem is I can't use the standard MONTH() function because for accounting purposes, the tax month is 16th - 15th. So July 13 would be considered to be in the June/July tax month, while July 21 would be considered to be in the July/August tax month.
I'm assuming I will need to maintain a table of the specific cut off dates like so:
Month
Start
End
Jun/July
16th June
15th July
etc.
But I can't work out how to use this as a lookup table to achieve what I want. Any thoughts appreciated.
I think this should work if your date is in A1:
=IF(DAY(A1)>15,TEXT(A1,"MMMM")&"/"&TEXT(A1+20,"MMMM"),TEXT(A1-20,"MMMM")&"/"&TEXT(A1,"MMMM"))
If sort order is important (e.g. in a subsequent pivot table) I would use this:
=IF(DAY(A1)>15,TEXT(A1,"MM MMMM")&"/"&TEXT(A1+20,"MMMM"),TEXT(A1-20,"MM MMMM")&"/"&TEXT(A1,"MMMM"))
Another way to specify the sort order is maintaining a separate table with sort order column. It's a completely different approach.
use:
=ARRAYFORMULA(IF(A2:A="",,IF(DAY(A2:A)<16,
TEXT("1/"&MONTH(A2:A)-1, "mmmm")&"/"&TEXT("1/"&MONTH(A2:A), "mmmm"),
TEXT("1/"&MONTH(A2:A), "mmmm")&"/"&TEXT("1/"&MONTH(A2:A)+1, "mmmm"))))

Google Sheets not calculating right?

can it be that Google Sheets is not calculating right?
=DAYS360(DATE(2016;12;31); date(2017;1;1))
is 1 and also this is 1 but is should be 2:
=DAYS360(DATE(2016;12;30); date(2017;1;1))
Whats wrong here?
I think it is because of the formula that is set to 360 days. It is said here that DAYS360 - Days between two dates on a 360-day year. So it means that you will only have a 30 days a month not including the date 31 in the months of (Jan, March, May, July, Aug, Oct and Dec).
For example, you use this =DAYS360(DATE(2016,10,25), date(2016,10,30)) so the expected output is 5 - which is correct
If you use =DAYS360(DATE(2016,10,25), date(2016,10,31)) the expected output is 6 - because you specify the date 31.
But, if you use =DAYS360(DATE(2016,10,25), date(2016,11,3)), the output is 8 not 9 - because it did not include the date 31.
I hope I explained it clearly.

Get date from week number in Google Sheets

If I have week 7 in 2017 what week date is the Monday in that week in Google Sheets?
=DATE(B9,1,1)-WEEKDAY(DATE(B9,1,1),3)+7*(WEEKDAY(DATE(B9,1,1),3)>3)+7*(A9-1)
is the least complicated formula I know which works for week numbers in Sweden (i.e. Monday first day of week, ISO rules for what is week 1).
Short answer (A1==Week, B1==Year):
=DATE(B1;1;1)+((A1-1)*7)-WEEKDAY(DATE(B1;1;1);3)
Long answer:
DATE(<year>;1;1) // days since 1970 until the frist day of the year
plus
((<week number>-1)*7) // how many days into the year is this week
minus
WEEKDAY(DATE(<year>;1;1);3) // how many extra days from previous year in first week
PS:
This assumes monday as the first day of week you have to change the arguments for WEEKDAY to change it to sunday
Because of this definition (https://en.wikipedia.org/wiki/Week) the 4th of January must be used instead the 1st. The 4th of January is the first day which is always in the week 1.
=DATE(B1;1;4)+((A1-1)*7)-WEEKDAY(DATE(B1;1;4);3)
If you are using ISO weeks, the accepted answer doesn't account for weeks overlapping on 2 technical years like 2020-w53, which is from 28 Dec 2020 until 3 Jan 2021.
Therefore I'm using this formula instead:
=DATE(K2,1,1)-WEEKDAY(DATE(K2,1,1),2)+7*(WEEKDAY(DATE(K2,1,1),2)>3)+7*(L2-1) +1
Where K is the Year, and L is the Week number (split in 2 columns from yyyy-ww)
to have it in an arrayformula:
=ArrayFormula(if(K2:K="",, DATE(K2:K,1,1)-WEEKDAY(DATE(K2:K,1,1),2)+7*(WEEKDAY(DATE(K2:K,1,1),2)>3)+7*(L2:L-1) +1 ))
You can use =ArrayFormula(if(E2:E="",,split(E2:E,"-"))) to split yyyy-ww in two columns.
NOTE: This formula would return the Monday (Which is the first day of the week in international standard, ISO)
Worked this up for 2023. It will work through end of 2024 too .. that said the AND logic is flawed .. feel free to suggest something to make this better
=IFS(
AND(ISOWEEKNUM(A8)=52,YEAR(A8)<>YEAR(A7)),
DATE(YEAR(A8-1),1,1)-WEEKDAY(DATE(YEAR(A8-1),1,1),3)+7*(WEEKDAY(DATE(YEAR(A8-1),1,1),3)>3)+7*(ISOWEEKNUM(A8)-1),
DATE(YEAR(A8),1,1)-WEEKDAY(DATE(YEAR(A8),1,1),3)+7*(WEEKDAY(DATE(YEAR(A8),1,1),3)>3)+7*(ISOWEEKNUM(A8)-1)
)

How to convert MS excel date from float to date format in Ruby?

Trying to parse and XLSX file using roo gem in a ruby script.
In excel dates are stored as floats or integers in the format DDDDD.ttttt, counting from 1900-01-00 (00 no 01). So in order to convert a date such as 40396 - you would take 1900-01-00 + 40396 and you should get 2010-10-15, but I'm getting 2010-08-08.
I'm using active_support/time to do calculation like so:
Time.new("1900-01-01") + 40396.days
Am I doing my calculation wrong or is there a bug in active support?
I'm running ruby 1.9.3-mri on Windows 7 + latest active_support gem (3.2.1)
EDIT
I was looking at the older file in Excel with the wrong data - my script / console were pulling the right data - hence my confusion - I was doing everything right, except for using the right file!!!! Damn the all-nighters!
Thanks to everyone replying, I will keep the question here in case somebody needs info on how to convert dates from excel using ruby.
Also for anyone else running into this - spreadsheet gem DOES NOT support reading XLSX files at this point (v 0.7.1) properly - so I'm using roo for reading, and axlsx for writing.
You have an off-by-one error in your day numbering - due to a bug in Lotus 1-2-3 that Excel and other spreadsheet programs have carefully maintained compatibility with for 30+ years.
Originally, day 1 was intended to be January 1, 1900 (which would, as you stated, make day 0 equal to December 31, 1899). But Lotus incorrectly considered 1900 to be a leap year, so if you use the Lotus numbers for the present and count backwards, correctly making 1900 a common year, the day numbers for everything before March 1st, 1900, are one too high. Day 1 becomes December 31st, 1899, and day 0 shifts back to the 30th. So the epoch for date arithmetic in Lotus-based spreadsheets is really Saturday, December 30th, 1899. (Modern Excel and some other spreadsheets extend the Lotus bug-compatibility far enough to show February 1900 actually having a 29th day, so they will label day 0 "December 31st" while agreeing that it was a Saturday! But other Lotus-based spreadsheets don't do that, and Ruby certainly doesn't either.)
Even allowing for this error, however, your stated example is incorrect: Lotus day number 40,396 is August 6th, 2010, not October 15th. I have confirmed this correspondence in Excel, LibreOffice, and Google sheets, all of which agree. You must have crossed examples somewhere.
Here's one way to do the conversion:
Time.utc(1899,12,30) + 40396.days #=> 2010-08-06 00:00:00 UTC
Alternatively, you could take advantage of another known correspondence. Time zero for Ruby (and POSIX systems in general) is the moment January 1, 1970, at midnight GMT. January 1, 1970 is Lotus day 25,569. As long as you remember to do your calculations in UTC, you can also do this:
Time.at( (40396 - 25569).days ).utc # => 2010-08-06 00:00:00 UTC
In either case, you probably want to declare a symbolic constant for the epoch date (either the Time object representing 1899-12-30 or the POSIX "day 0" value 25,569).
You can replace those calls to .days with multiplication by 86400 (seconds per day) if you don't need active_support/core_ext/integer/time for anything else, and don't want to load it just for this.
"Excel stores dates and times as a number representing the number of days since 1900-Jan-0, plus a fractional portion of a 24 hour day: ddddd.tttttt . This is called a serial date, or serial date-time." (http://www.cpearson.com/excel/datetime.htm)
If your column contains a date time, rather then just a date, the following code is useful:
dt = DateTime.new(1899, 12, 30) + excel_value.to_f
Also keep in mind that there are 2 modes of dates in an excel worksheet, 1900 based and 1904 based, which typically is enabled by default for spreadsheets created on the mac. If you consistently find your dates off by 4 years, you should use a different base date:
dt = DateTime.new(1904, 1, 1) + excel_value.to_f
You can enable/disable 1904 date mode for any spreadsheet, but the dates will then appear off by 4 years in the spreadsheet if you change the setting after adding data. In general you should always use 1900 date mode since most excel users in the wild are windows based.
Note: A gotcha with this method is that rounding might occur +/- 1 second. For me the dates I import are "close enough" but just something to keep in mind. A better solution might use rounding on fractional seconds to solve this issue.
You're doing your calculation wrong. How do you arrive at the expected result of 2010-10-15?
In Excel, 40396 is 2010-08-06 (not using the 1904 calendar, of course). To demonstrate that, type 40396 into an Excel cell and set the format to yyyy-mm-dd.
Alternatively:
40396 / 365.2422 = 110.6 (years -- 1900 + 110 = 2010)
0.6 * 12 = 7.2 (months -- January = 1; 1 + 7 = 8; 8 = August)
0.2 * 30 = 6 (days)
Excel's calendar incorrectly includes 1900-02-29; that accounts for one day's difference between your 2010-08-08 result; I'm not sure about the reason for the second day of difference.

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