Difference between DATEDIF unit "d" and "yd" - excel

I am trying to understand how the difference between DATEDIF(date1,date2,"d") and DATEDIF(date1,date2,"yd") in excel. It is very confusing when trying to deal with leap year dates.
for example
=DATEDIF("2/29/2020","3/1/2021","yd") gives 0.
but when I try to give
=DATEDIF("2/29/2020","3/1/2021","d") gives 1.
and one more thing is
=DATEDIF("2/1/2020","3/1/2021","yd") gives 29 and
=DATEDIF("2/1/2019","3/1/2021","yd") gives 28.
Some of the articles claim that year of start date is used for calculations so with that logic DATEDIF("2/29/2020","3/1/2021","yd") should give 1 instead of zero. Can someone explain how the calculations are being done and what year is being considered for the calculations?

From the docs you can see what is the difference.
To be explicit, the YD variant isn't taking year into account, thus showing different results in the case of leap year.

Related

How can I calculate the number of lost weather days in Excel?

I have done some programming in the past, so I would be able to figure this problem out in a programming language. But, I do not know how to proceed with accomplishing my task in an Excel spreadsheet. Any kind of guidance would be helpful because I am not familiar with anything but a basic use of MS Excel, so I don't even know which topics to search for to get some guidance on solving this problem.
Here is the breakdown for my problem:
I work for a construction company and I am keeping count of the number of days which need to be extended to a schedule deadline. All "lost weather days" are in a column (assume they are in chronological order and there are not bad dates like 2/32/22).
Contractually, we eat the first 5 lost weather days for any given month. But, if there are more than 5 lost weather days in any given month, then I need to add those days to a count by which the schedule deadline can be extended. So, any time a month has more than 5 lost weather days, I need to start counting.
For example:
DATE
1/1/23
1/2/23
1/13/23
1/14/23
1/25/23
1/26/23
1/27/23
2/1/23
2/12/23
Here, 1/6/23 and 1/7/23 need to be counted while all of the other dates are ignored because 1/1/22, 1/2/22, 1/3/22, 1/4/22, and 1/5/22 are the first five days in January 2023. So, I should have a cell with a value of 2.
Any help or guidance would be appreciated. Thank you.
I haven't tried anything specific because I am unfamiliar with excel at the moment.
=LET(m,EOMONTH(TRANSPOSE(A2:A10),0),
f,FREQUENCY(m,m),
SUM(IF(f>5,f-5)))
This first converts the dates in the same month(/year) to the same date being the end of that month.
Then FREQUENCY counts the number of days being the same per month. Then, if the frequency is higher than 5, 5 is substracted, else ignored.
For older Excel versions:
=SUM(
IF(
FREQUENCY(
EOMONTH(TRANSPOSE(A2:A10),0),
EOMONTH(TRANSPOSE(A2:A10),0)
)>5,
FREQUENCY(
EOMONTH(TRANSPOSE(A2:A10),0),
EOMONTH(TRANSPOSE(A2:A10),0)
)-5)
)
With Office 365:
=LET(rng,A2:A10,uq,UNIQUE(DATE(YEAR(rng),MONTH(rng),1)),SUM(BYROW(uq,LAMBDA(a,MAX(0,COUNTIFS(A2:A10,">="&a,A2:A10,"<"&EOMONTH(a,0)+1)-5)))))

Excel subtract X days from date and then find last specific workday date

here's my problem:
We have an Excel sheet at work in order to manage various tasks all set on individually specified timelines - we're talking hundreds of tasks per month with dates that are currently all being maintained manually.
Let's say we have Task A and that task has a Due Date. That Task is split into several subtasks, all with their individual due dates. Date 1 would then always be Due Date - 10 days, Date 2 would be Due Date - 20 days, Date 3 would be Due Date - 17 days and so on. This then creates a neat timeline of when everything needs to be done.
That in itself would be easy enough, problem is that all of these subtasks have to be done on a specific workday as well. Meaning that subtask 1 would not only have to be done Due Date - 10 days, but it would also have to fall on a Monday - if for whatever reason Due Date - 10 would happen to fall on like a Wednesday, it would have to subtract another 2 days. And then the real problem is that Date 2 and 3 each have to fall on different workdays and Task B has an entirely different schedule again.
Now, the first thing that came to my mind was attempting to just nest a couple IFs - and I've even managed to come up with a working formula for that. Problem here is that it's so stupidly long and (thanks Excel) utterly unreadable - if for some reason someone else had to change something about it or troubleshoot the entire file 1-2 years from now, they'd probably have to spend at least an hour reconstruct how the hell any of it actually worked. Which doesn't sound particularly appealing to us.
Here's a screenshot to help illustrating the situation:
And here's a draft of the current formula that I'm really not happy with, despite it somewhat doing the job:
=IF(AND(WEEKDAY(K2-VLOOKUP(B2,Table1,3,FALSE),11)>5,VLOOKUP(B2,Table1,5,FALSE)=0),(K2-VLOOKUP(B2,Table1,3,FALSE))-(WEEKDAY(K2-VLOOKUP(B2,Table1,3,FALSE),11)-5), IF(VLOOKUP(B2,Table1,5,FALSE)=0,K2-VLOOKUP(B2,Table1,3,FALSE), IF(WEEKDAY((K2-VLOOKUP(B2,Table1,3,FALSE)),11)=0,K2-VLOOKUP(B2,Table1,3,FALSE), (VLOOKUP(B2,Table1,5,FALSE)-WEEKDAY(K2-VLOOKUP(B2,Table1,3,FALSE),11))+K2-VLOOKUP(B2,Table1,3,FALSE))))
My question is now: Does anyone have an idea how to solve this in a less confusing and unclear manner? I was trying to get something done using =CHOOSE() but ultimately ended up with the same problem of eventually having to resort to 7 IFs and dozens of LOOKUPs, making the final formula just as long. I wouldn't be disinclined towards some kind of helper table that asigns the last 7 days and their workdays to every single day of the year... but I don't think tossing another 20,000 calculated cells into a file that already has tens of thousands other calculated cells would really be a serviceable alternative... or make the situation any less obscure at all tbh.
So, anyone any idea how to go about this? Or is there really no realistic alternative than to use a bunch of IFs?
Edit: Forgot to mention that 1 special case:
There's also the situation when a date doesn't have to fall on a specific workday - in which case it's simply due date - X days. The problem here is that in those cases the dates could fall on a weekend, so the formula would have to move these dates to the previous Friday as well.
Assume you have some date and you want to "back up" ten days and then to the preceding Monday, unless the resultant date is a Monday. The general formula would be something like:
=A2-10+1-WEEKDAY(A2-10-DOW)
Where DOW translates into
Sunday=0
Monday=1
Tuesday=2
...
You should be able to modify your formulas to use this algorithm for day of the week.
If the two tables are named thisTable and keyTable, the following 365 formula is one way of implementing:
If your tables are as below, you can enter the formula in B2 and fill down and across. The references should self-adjust and return the proper dates.
Note that in keyTable, I enter the day of the week DOW as defined above, and not the textual date.
=LET(dys,VLOOKUP(thisTable[#[Task]:[Task]],KeyTable,COLUMNS($A:A)*2,FALSE),
dow,VLOOKUP(thisTable[#[Task]:{Task]],KeyTable,COLUMNS($A:A)*2+1,FALSE),
due,thisTable[#[DueDate]:[DueDate]],
IF(dow="flexible",WORKDAY(due-dys+1,-1),due-dys+1-WEEKDAY(due-dys-dow)))
If you want to have the result be the closest workday, instead of the preceding workday, then you need to add two clauses to the LET function
Calculate the subsequent workday date
Then use an IF to return the closest one to the original target
eg:
=LET(dys,VLOOKUP(thisTable[#[Task]:[Task]],KeyTable,COLUMNS($A:A)*2,FALSE),
dow,VLOOKUP(thisTable[#[Task]:[Task]],KeyTable,COLUMNS($A:A)*2+1,FALSE),
due,thisTable[#[DueDate]:[DueDate]],
dayPrev,IF(dow="flexible",WORKDAY(due-dys+1,-1),due-dys+1-WEEKDAY(due-dys-dow)),
daySubseq,IF(dow="flexible",WORKDAY(due-dys+1,-1),due-dys+7-WEEKDAY(due-dys-1-dow)),
IF((daySubseq-due+dys)>3,dayPrev,daySubseq))

Is there an Excel formula to compare two dates to see if they are >90 days apart and then repeat for dates after that?

I apologize for how I worded the title, but I am having a hard time really distilling my issue into a snappy soundbite.
My problem is this: Using the data below, for each User ID I need to find each instance that a date differs from a previous one by 90 or more days. BUT then, once 90 day difference is found, it needs to "reset" and look for dates 90 or more days from that.
Basically, I want a formula that can reproduce the Result column in the below table.
For example, note how for User ID 1 that the first 8/30 date yields a positive result, but neither the second 8/30 nor the 9/21 do, since they are both less than 90 days distant from 8/30. But then 12/26 does yield a positive result, since it is 118 days past the last positive result.
I really appreciate any help you can offer.
Thanks!!
Eq#1: =DATEDIF(B3,C3,"D")
Eq#2: =IF(E3>90,"Do a little dance","Frowny Face")

How to display the past 17 trading days (business days) when looking up Stock History in excel

I'm using the new STOCKHISTORY function in Excel and I'd like to always display the past 17 trading days from the point I indicate. The problem is with long weekends and holidays this alters the amount of business between two dates. I'm not sure if this will be a difficult question because I think the solution is not dependent on the fact that I'm using the STOCKHISTORY function. I have attached a photo with a simple explanation. On the left the formula for STOCKHISTORY is =STOCKHISTORY(E2,C4-C6,C4,0,1,0,2). This displays 17 business days because 22 is the magic number. On the right though if I query July 22nd with 22 day difference I only get 16 days. This is further wrong on many other dates.
I am open to having a separate reference on another sheet that has dates/formulas. I tried this but couldn't figure out a formula to pull down. Photo B displays an example of the correct number of dates that would show 17 trading days. I am also open to displaying more than 17 trading days as in the future I will need to alter the amount of trading days needed (I might need to display 15 days or 20 days).
In my head I feel like the answer has something to do with the NETWORKDAYS function and/or I should make a list of all the trading days in a year and then make a formula taking the current day and taking away a specific day. Or I could be totally wrong and the answer is obvious.
So I figured out an answer after reading some documentation. There is most likely better answers but it solves the problem enough.
So I created a list of all trading days (business days) as you can see in column O. Then in Column L a list of nearby holidays (Only needed a few exceptions). Then using the formula =(O35)-(WORKDAY(O36,-17,$L$35:$L$36)) I get the right solution which I verified in my example photo posted earlier. You could theoretically get a different number when doing your own calculations (i.e the answer 24 and 23 are both correct).

How to calculate a... median? of hour/day/month of occurence?

My problem concerns day of month however, I can see that the same logic would apply to month number or hour number or any other variable that ends on some value and then starts from 0 again.
It is defined as follows: I'm trying to calculate a day of month when a payment is made to use it for a forecast. So I have for example for one case:
1 May 2016
2 June 2016
30 June 2016
29 July 2016
6 September 2016
A simple average would give me 14th, and the median would give me 6th. But the result I'm looking for is more like the 1st.
I see I could do it somehow by calculating geometric median, or euclidean distances after placing the points on a circle etc, but I believe it can be approached in a much simpler way. I also see that solving this problem with standard means and averages would cause a situation where it gives more than one result.
But if we add an assumption that it should occur once in 30 days/a month? Wouldn't this assumption make the problem easier?
Please let me know if you solved a similar problem before or if you have any ideas
If the result you are "looking for is more like the 1st", then I would hazard a guess that you are really looking at a series of monthly payments (perhaps falling due on the first of each month or the first working day of each month) and you want some measure of the deviation between the due date and the actual date of payment.
If that is the case then simply calculate the difference in days between the due date and the actual date of payment for each monthly payment (following a consistent convention such as positive values denote late payment and negative values are early) and then apply your chosen measure (median, mean, etc) to the series of differences.

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