US convention different in spreadsheet functions (Libre, Google Sheets, etc.) - excel

The Excel/Google-Sheets/LibreOffice function DAYS360() returns the number of days between two dates based on a 360-day year. 0 (default) is used for the US-based method and here are some examples
A = 30 Apr 2016, B = 29 Feb 2016, DAYS360(A, B) = -61
A = 29 Feb 2016, B = 30 Apr 2016, DAYS360(A, B) = 60
This seems ok according to the rules here
But the Excel/Google-Sheets/LibreOffice function YEARFRAC() returns the number of years, including fractional years, between two dates using a specified day count convention. Even here 0 (default) uses US method, (US (NASD) 30/360) which I presumed will also be equal to the value of number of days calculated by DAYS360 * the number of seconds in a day/number of seconds in 360 days. The values in the sheets are as follows
A = 30 Apr 2016, B = 29 Feb 2016, YEARFRAC(A, B) = 0.1666666667
A = 29 Feb 2016, B = 30 Apr 2016, YEARFRAC(A, B) = 0.1666666667
Since it can be seen that the absolute value of the DAYS360 is different by one, the YEARFRAC value is same and assumes 60 days according to the presumption made above, so are the US-based convention mentioned here is the same as mentioned for DAYS360.
If not, what are the exact rules for this one, or is there some other problem?
NOTE: Tested these values on Google Sheets and Libre Office.

DAYS360 parameter 3:
0 indicates the US method - Under the US method, if start_date is the last day of a month, the day of month of start_date is changed to
30 for the purposes of the calculation. Furthermore if end_date is the
last day of a month and the day of the month of start_date is earlier
than the 30th, end_date is changed to the first day of the month
following end_date, otherwise the day of month of end_date is changed
to 30.
1 or any other value indicates the European method - Under the European method, any start_date or end_date that falls on the 31st of
a month has its day of month changed to 30.
YEARFRAC parameter 3:
0 indicates US (NASD) 30/360 - This assumes 30 day months and 360 day
years as per the National Association of Securities Dealers standard,
and performs specific adjustments to entered dates which fall at the
end of months.
1 indicates Actual/Actual - This calculates based upon the actual
number of days between the specified dates, and the actual number of
days in the intervening years. Used for US Treasury Bonds and Bills,
but also the most relevant for non-financial use.
2 indicates Actual/360 - This calculates based on the actual number of
days between the specified dates, but assumes a 360 day year.
3 indicates Actual/365 - This calculates based on the actual number of
days between the specified dates, but assumes a 365 day year.
4 indicates European 30/360 - Similar to 0, this calculates based on a
30 day month and 360 day year, but adjusts end-of-month dates
according to European financial conventions.

Related

Excel: calculate which occurance of a weekday, within the month, from any given date e.g. fifth Friday

I am not very good at Excel. In the NHS (UK) we often schedule activity by looking at the columns on a calendar (e.g. All day theatre list Mondays week 1,3,5). This means on the first Monday, third Monday and if present fifth Monday. Using a printed calendar you can see the columns, for example Mondays in Jan 2023 where there are five.
When planning, it would be great to have a formula that would accept a date, and return the ordinal of the weekday for that month e.g.
Jan 02 2023 = 1
Jan 28 2023 = 4
Jan 29 2023 = 5
Jan 30 2023 = 5
I have searched and found the WEEKNUM function, but this counts rows on the calendar not giving the result I need.
Any help gratefully received
Kind Regards Gavin Holt
This should return those values:
=-INT(-(DAY(YourCellWithTheDate))/7)

Using pandas, how can I find out if my customer made a purchase last month or two months ago?

I'm new to python and new to pandas. Of course, if my project used exact dates, I could easily do this, but unfortunately, the date type is a little different, and as you can see, the sign 08 is after the year 1401, which means it is the eighth month of the year 1401.
I currently know that these 3 customers have bought from me this month. But I want to know if these 3 customers bought from me in the previous month or two months ago? If they do, I will give them a discount.
Of course, I should also say that the number 08 is not always fixed, but it could be 09 in the next month. I just want to know if they bought from me 1 month ago or not?
According to the picture, now only Sara should get a discount
You could convert the purchase date to an integer and calculate the number of months from there.
For instance, you have the purchase month 1901/07 and you want to know in 1901/08 how many months the last purchase took place. So you convert both values to integers and subtract them (190108 - 190107 = 1).
import pandas as pd
df = pd.DataFrame({'customer': ['david', 'sara'], 'date': ['1901/03', '1901/07']})
# Manually setting the reference month (190108 for Year 1901 and Month 08)
df['months'] = 190108 - df['date'].replace('/', '', regex=True).astype(int)
# Check if eligible for discount
df['discount'] = df['months'].isin([1, 2])
customer
date
months
discount
0
david
1901/03
5
False
1
sara
1901/07
1
True
To compare with today's month you could to the following:
df['months'] = int(pd.Timestamp.now().strftime('%Y%m'))\
- df['date'].replace('/', '', regex=True).astype(int)

Limit max day of Data for all months

I need to calculate, over months, the value of Sales in every month limiting the max day of my data = my Day(DateTimeNow()) - 1.
Examples:
Today is 25 of march, i wanna see in my bar chart the total of Sales until day 24 for january, february and march.
Today is 02 of april, my bar chart will show the sales of day 1 for january, february, march and april.
I've tried using limit data in my graph like so I set the max day of my Date to be the Day(DateTimeNow()) - 1
Max(Day([DATE])) = Day(DateTimeNow()) - 1
That way I set the max Day for my date to be equal my Day - 1
I've tried using ParallelPeriod too.
I expect that using:
Max(Day([DATE])) = Day(DateTimeNow()) - 1
I've got like:
Max(Day([DATE])) = 31
Day(DateTimeNow()) - 1 = 02
( Max(Day([DATE])) = Day(DateTimeNow()) - 1 )
I know that this results in a boolean expression, so:
31 = 02 -> False
But i just want to set the Max Day to be 02.
This expression below should fit your needs. Put this expression in the Limit data using expression of the visualization options.
Day([DATE])<Day(DateTimeNow())-1
It takes, for each months, the days before current day - 1. If we are on the first of the month, then no data will be available.

Excel find date difference between minimum and maximum date in month

I'm trying to fix up a formula I have that's having some issues. It's supposed to track # days invoiced in a month, so the high-level idea is to take the maximum date in a month and subtract the minimum date in the month, and on error subtract the 1st day of the month. My current formula has issues adjust for invoices that may cross months, an example being 1/25 - 2/3 where if this were the only invoice, January should show 7 days invoiced and February would show 3. If there were another invoice from 2/15 - 2/28, I would want Feb to show the maxed invoice days, 14 in this example.
For reference here's what a table could look like:
A B C D E F
start month end month invoice begin invoice end Month Max Days invoiced
jan 1 feb 1 1/25/14 2/3/14 1/1 7
feb 1 feb 1 2/15/14 2/28/14 2/1 14
3/1
etc.........
I tried the formula below but it was erroring out, plus I don't think it will account for gaps in invoices like in my example.:
=IF(B2:B100=X1,MAX(D2:D100),) - IF(A2:A100=X2,MIN(C2:C100),A2)
'where column X is a list of months, X1 = 1/1, X2 = 2/1, etc.
No luck with this formula either, keeps erroring out and giving 0 values:
{=DATEDIF(IF(A2:A100=E2,MIN(C2:C100),),IF(B2:B100=E2,MAX(D2:D100),),"d")}
I appreciate your help!
Not sure exactly what you are looking for but you could probably make use of the EOMONTH() function. Here's an example of it:
=EOMONTH(A2,0)-A2+1
by the way - here is how you would get the start of the month:
=EOMONTH(TODAY(),-1)+1
Try the following per your comment below:
"I think this could be useful but I'm not sure it would work if the invoice end was, say, 2/21 or anytime before the EOM"
=IF(B3>=EOMONTH(A3,0),EOMONTH(A3,0)-A3+1,B3-A3+1)

Numerical month to character month in excel

Is there a pre-installed function that directly converts 08 to Aug, 10 to Oct?
Currently I use text(date(0,have,1),"mmm").
You could simplify like this: =TEXT("8/0","mmm").
Update
I've come up with a new technique: =TEXT(number * 30,"mmm"):
How it works
Dates are stored as numbers in Excel. The number 1 is the date Jan 1, 1900; 2 is Jan 2, 1900; etc.
The 30th day in 1900 is in January; the 60th day is in February; the 90th day is in March.
Every multiple of 30 between 30 and 360 is in a different month. So we can simply multiply 30 by a number between 1 and 12, and the TEXT function will give us the month.
You can use
MonthName(yourmonthNumber)
or
MonthName(yourmonthNumber, True) 'to abbreviate the name
Or did you mean a worksheet function?

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