Excel find date difference between minimum and maximum date in month - excel

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)

Related

how to calculate the date from the year, week-of-year and day-of-week in EXCEL?

I have the Year, Week-of-Year and Day-of-the-Week as follows:
Year = 2022 (A2) ; Week Year = 35 (B2); Week Day = 4 or Thursday (C2)
and I would like to estimate the Date as dd.mm.yyyy, which is highlighted in yellow as it shows in the EXCEL picture.
I tried many formulas, but I am sure there might be an easy one.
I think you are counting the weeks starting from zero because for 9/1/2022 (YYYY/MM/DD format) the corresponding week is 36 as per the result of function WEEKNUM(DATE(2022,9,1)). In order to use the logic to multiply the number of weeks by 7. You need to use as a reference the first day of the year, if it was a Sunday, if not then go back to the previous Sunday, so you can count the entire week. Bottom line use as a reference date, the Sunday of the first week of the year, not the first day of the year (YYYY/1/1)
Here is the approach we use in cell E2:
=LET(y, A2:A6, wk, B2:B6, wDay, C2:C6, fDay, DATE(y,1,1), seq, SEQUENCE(7),
fDay - IF(WEEKDAY(fDay)=1,0, WEEKDAY(fDay,2)) + 7*wk
+ XLOOKUP(wDay, TEXT(seq,"dddd"), seq-1))
We use the LET function to avoid repeating the same calculation. The following expression finds the previous Sunday if the first day of the year (fDay) was not a Sunday:
fDay - IF(WEEKDAY(fDay)=1,0, WEEKDAY(fDay,2))
The XLOOKUP function is used to get the numeric representation of the weekday and use the TEXT function to generate the weekdays in a long format. Since we count the entire week, if the weekday is a Sunday (column C in my screenshot), then we don't need to add any day to our reference date, that is why we use seq-1.
Here is the output for several sample data. Assuming the week count starts with zero, if not the formula needs to be adjusted as also the input data.
Notice that the year 2021 started on a Friday, so if we want to find a day for the first week (0) before Friday it will return a date from the previous year. Like in the case of Monday. If you want an error message instead, then the formula can be modified as follow:
=LET(y, A2:A6, wk, B2:B6, wDay, C2:C6, fDay, DATE(y,1,1), seq, SEQUENCE(7),
result, fDay - IF(WEEKDAY(fDay)=1,0, WEEKDAY(fDay,2)) + 7*wk
+ XLOOKUP(wDay, TEXT(seq,"dddd"), seq-1),
IF(YEAR(result) <> y, "ERROR: Date from previous year", result))
I found the solution:
Year = 2022 (A2) ; Week Year = 35 (B2); Week Day = 4 or Thursday (C2)
=DATE (A2,1,3)-WEEKDAY(DATE(A2,1,3)) + 7 * B2 + C2 - 6
I found this solution, but you need to do further testing if it really works.
I calculate month from week: =+MONTH(DATE(YEAR(A2);1;1)+B2*7-1)
I calculate week day number from week day name: =MATCH(D2;{"Monday";"Tuesday";"Wednesday";"Thursday";"Friday";"Saturday";"Sunday"};0)
And then make date using: =DATE(A2;C2;E2)

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)

Excel formula to calculate elapsed minutes between 2 date timestamps only counting minutes during work hours

I have an excel sheet with about 50,000 records where I need to find the number of minutes between two date timestamps but I need to exclude any minutes that occurred during the times we are not working.
Our schedule is M-F 8:30am-5:30pm, Saturdays 8:30am-1:30pm
We don't work Sundays or holidays.
As an example
Cell B2: [7/3/2020 2:16:21 PM]
Cell C2: [7/6/2020 9:20:23 AM]
The manually calculated answer for this one should be about 244 minutes. Task started Friday afternoon, Saturday was a holiday, don't work Sundays, task completed at 9:20am on Monday.
Usually, I come here and start writing a question and by the time I've understood my own problem well enough to post a question I have figured it out on my own but not this time! Help!
Update:
#ForwardEd shared this...
=((I2-H2)
-MAX(0,(NETWORKDAYS.INTL(H2,I2,"0000011",$M$2:$M$12)-1+(WEEKDAY(I2,1)=7)))*TIME(15,0,0)
-MAX(0,(NETWORKDAYS.INTL(H2,I2,"1111101",$M$2:$M$12)-(WEEKDAY(I2,1)=7)))*TIME(19,0,0)
-NETWORKDAYS.INTL(H2,I2,"1111110",$M$2:$M$12)-(NETWORKDAYS.INTL(H2,I2,"0000000")
-NETWORKDAYS.INTL(H2,I2,"0000000",$M$2:$M$12)))*24*60
Where H:H is the Start Date Timestamp and I:I is the Response Date Timestamp and M2:M12 contains my holiday list.
It worked beautifully until I ran into an example like this:
H2 - 07/26/2020 7:48:45 PM
I2 - 07/27/2020 8:57:58 AM
The net result was -650.78333. It looks like anything that starts one one day and ends on the next is coming back as negative.
We want to measure the average response time in minutes for the applications that require manual underwriting. These start timestamps are times that loan applications were received online so they could come in any time of day. The stop times are timestamps that represent the system recorded response time. i.e. the timestamp where an underwriter first did something with the loan application. If a loan application was received at 7pm and was not auto-decisioned then a manual underwriter will need to do something with it the next day when we start working.
If that application came in at 7pm on Wed and is decisioned by an underwriter at 8:46am on Tuursday, we would want to document 16 minutes for that application - not 826 counting the hours between 7pm and 8:30am.
What you want to look at is NETWORKDAYS.INTL. Use this in conjunction with the custom settings to determine the number of Saturdays, Sundays and for the number of days in between your start and end time. You know you have X amount of time per day that is non working time, and Y amount per Saturday.
Then you formula in essence becomes
(End time - start time) - X * No. Weekdays - Y * No. Saturdays - No. Sundays - No. Holidays
Now there will be some tricks in there in order to count your days. but that is the gist of what it boils down to in a formula.
The formulas that are doing the brunt of the work are:
WORKDAY
NETWORKDAYS.INTL
TIME
I avoided the use of an if statement by using a boolean operation that excel will resolve from TRUE/FALSE to 1/0 when sent through a math operator. Side note: I read somewhere that this is also faster than an IF statement, but have no way of proving it and really does not matter on a small number of calculations.
WORKDAY
This formula will return the day of the week for a given date, and a set day of the week to be 1. It will be need in this solution to determine if the end date is a Saturday which has a value of 7 in default setup up as well when option 1 is picked. The format for the formula is:
WORKDAY(Excel Serial date, day 1 of the week)
For this solution
WEEKDAY(B3,1)
NETWORKDAYS.INTL
This formula will be used to count the number of specific days a start and an end date. It can exclude a custom weekend or count a custom week. If it is supplied with a list of dates that are holidays they can be excluded as well. The basic format of the formula is:
NETWORKDAYS.INTL(Start Date, End Date, Custom week choice or workweek pattern, range of holiday dates)
When entering the formula it will give you a list of predefined options for the weekend choices. It will not talk about the pattern.
The pattern is a string 7 digits long consisting of 1 or 0. 0's represents the days you want to count and 1's are days you want to ignore. An important part of the pattern is that the first entry is MONDAY. "1010111" would count only Tuesdays and Thursdays.
TIME
Excel stores date as an integer. 1 represents 1st of January 1900, 2 the 2nd of January 1900 and so on. Time is stored as a decimal or if you prefer the percentage/fraction of a day or 24 hour period. So rather than figuring out the math to determine what percentage of a day X number of hours is, it is simpler to let excel calculate it for us and make the number a little more understandable to someone who may be deciphering the formula later. The basic format of the formula is:
TIME(Hours, Minutes, Seconds)
So as stated earlier, 6 key components need to be determined:
X - Amount of non working time after a weekday
Y - Amount of non working time after a Saturday
Number of weekdays
Number of Saturdays
Number of Sundays
Number of holidays
1) Determine Weekday Non-Working Hours
Based on the supplied information that work day stops at 1730 and starts as 0830. There are a couple of ways of doing the math. Subtract the working hours from 24 hours or count the non work hours at the end of the day and add them to the non work hours at the start of the day.
24 - (17.5 - 8.5) = 15
or
(24 - 17.5) + (8.5 - 0) = 15
For this example 15 will be hard coded into the final formula
2) Determine Saturday Non-Working Hours
Similar to above. Note that we are ignoring Sunday as it is a designated non working day which we already know is 24 hours or 1 day. We are just interested in the time between end of shift Saturday and start of the next normal working Monday. So it really gets calculated the same with just with difference end of shift time.
24 - (13.5 - 8.5) = 19
or
(24- 13.5) - (8.5 - 0) = 19
For this example 19 will be hard coded into the final formula
3) Determine Number of Weekdays
Based on the description earlier of of NETWORKDAYS.INT and working with the assumption that holidays are stored in the range F2:F2, and using a pattern of "0000011" the number of weekdays the formula will be as follows:
=NETWORKDAYS.INTL(B2,B3,"0000011",F2)
For this example the formula is place in cell F6
4) Determine Number of Saturdays
Similar 3) adjust the pattern to only select Saturdays by using "1111101"
=NETWORKDAYS.INTL(B2,B3,"1111101",F2)
For this example the formula is place in cell F7
5) Determine Number of Sundays
Similar 4) adjust the pattern to only select Saturdays by using "1111110"
=NETWORKDAYS.INTL(B2,B3,"1111110",F2)
For this example the formula is place in cell F8
6) Determine Number of Holidays
To get the number of holidays there is not a direct way of doing it. Instead take the difference between all days counted without holidays being factored in and all days counted with holidays counted in.
=NETWORKDAYS.INTL(B2,B3,"0000000")-NETWORKDAYS.INTL(B2,B3,"0000000",$F$2:F2)
For this example the formula is place in cell F9
Now at this point I would love to say just substitute all of the above into the generic formula, but there are a couple of special cases that need to be taken care of. You may have also noted I have not used the WEEKDAY formula yet.
So in order to count the number of days to which X is going to apply, its really the number of days minus 1. The minus 1 is because you want to cont the intervals between days, not the number of days themselves. This gets a little bit more trickier when the end day is a Saturday because there is still an interval there but Saturday is not counted as a weekday. So the True count for number of weekday intervals is:
=MAX(0,(F6-1+(WEEKDAY(B3,1)=7)))
I originally had the MAX(0, calc) in there to prevent the posibility of the day count being negative. After arriving at this final format it may not be needed and you might get away with the following but its untested:
=F6-1+(WEEKDAY(B3,1)=7)
This same concept needs to be applied to your Saturday count. If you job ends on Saturday you do not need to subtract the non working hours after the last Saturday. You formula will look like:
=MAX(0,(F7-(WEEKDAY(B3,1)=7)))
and again further testing is required to make sure MAX can be removed, but if it can then the formula would look like:
=F7-(WEEKDAY(B3,1)=7)
So now with the understanding how dates and times are stored, determine the time difference between start end end time and subtract all the non working hours.
=(B3-B2)-MAX(0,(F6-1+(WEEKDAY(B3,1)=7)))*TIME(15,0,0)-MAX(0,(F7-(WEEKDAY(B3,1)=7)))*TIME(19,0,0)-F8-F9
Now you will not want to use helper cells, so you can take each of the individual formula from F6 to F9 and wind up with:
=(B3-B2)-MAX(0,(NETWORKDAYS.INTL(B2,B3,"0000011",F2)-1+(WEEKDAY(B3,1)=7)))*TIME(15,0,0)-MAX(0,(NETWORKDAYS.INTL(B2,B3,"1111101",F2)-(WEEKDAY(B3,1)=7)))*TIME(19,0,0)-NETWORKDAYS.INTL(B2,B3,"1111110",F2)-(NETWORKDAYS.INTL(B2,B3,"0000000")-NETWORKDAYS.INTL(B2,B3,"0000000",$F$2:F2))
The formula looks unruly, but is easier to understand when broken down into its parts.
Now the last step is to get the answer to display in minutes. There are two choices.
You can leave it as it is in an excel serial date format and change the formatting of to a custom format of [m]. The [ ] will force it into minutes and prevent spill over to hours. It will also round to the nearest minute.
You can convert the results to minutes by multiplying by 24*60 and the value will be in minutes and decimal of minutes.
Note that:
A11 has Time formatting applied
A12 has General formatting applied
A14 has custom formatting of [m] applied
It should be something like this:
Create a calendar table with the workinghours for each days in the year you have data in
Date | StartTime | End time
1/1/2020 1/1/2020 8:30:00 PM 1/1/2020 5:30:00 PM
...
7/3/2020 7/3/2020 8:30:00 PM 7/6/2020 5:30:00 PM
...
12/31/2020
Then paste this code in a module
Function CalcDays(dStart As Date, dEnd As Date, daysCalendar As Range)
Dim Cell As Range
Dim MinDaysCalendar As Date, MaxDaysCalendar As Date
Dim aWSF As WorksheetFunction
Set aWSF = Application.WorksheetFunction
'check the minimum en the maximum date in the calendar
With aWSF
MinDaysCalendar = .Min(daysCalendar)
MaxDaysCalendar = .Max(daysCalendar)
End With
'if the date you check is not in the calendar, exit the function
If dStart < MinDaysCalendar Or dStart > MaxDaysCalendar Then
MsgBox "Date not in calendar"
Exit Function
End If
If dEnd < MinDaysCalendar Or dEnd > MaxDaysCalendar Then
MsgBox "date not in calendar"
Exit Function
End If
'sum the time of all the dates between the start and the end
'pick min and max in order to start and stop at the right time per day
Dim tempTime As Integer
With daysCalendar
For i = 1 To .Rows.Count
If .Cells(i, 2).Value >= CLng(dStart) And .Cells(i, 3).Value <= CLng(dEnd) Then
daytime = aWSF.Max(.Cells(i, 2).Value, dStart) - aWSF.Min(.Cells(i, 3).Value, dEnd)
End If
tempTime = tempTime + daytime
Next i
End With
'return the total time
CalcDays = tempTime
End Function
You can call the function by typing =calcdays in a cell and then give the startDay, endDay and calendar column as parameters.
There might still be some flaws in this code but I think we can manage those.

How to find a trend/forecast result 14 days from today

I have looked into the Forcast & Trend formula but I cannot figure it out for the life of me.
I want to work out the trend 14 days from now.
I have a set of data:
A1 - A30 with dates
B1 - B30 with daily ticket count for the business.
I would like to make a result in another cell that would predict what the estimated total ticket count would be 14 days from now. I do not need all 14 days, just the 14th day.
If I was to try show you what the formula looks like in my head it would be:
=trend/forecast(B1:B30,14)
or
=Predict(B1:B30)*14
Unfortunately it is not as easy as that. How can I do this?
I think you want to use the Forecast function. The inputs you have do not match the correct format though.
FORECAST( x, known y's, known x's) where...
x = the series (or date) you want to forecast
known y's = historical tickets per day
known x's = historical dates (or series)
The below example allows you to forecast tickets for any date (Forecasted Date) given the historical information (table on left). If your table is not formatted with actual dates, just create a series (first day = 1, second day = 2, etc.) and forecast that way.
Given the historical data, the forecasted tickets for Aug 28th (14 days after last known value) are 16.7

How do I write an Excel formula to compare year-to-date to prior years & also account for leap years?

I’m trying to compare a measure as of today through the same day and month for the prior 4 years (e.g. through June 6 of 2016, 2015, 2014, etc.).
For each year, I decided to count the number of days since the beginning of the year, and sum my values through that number of days for each year.
To identify whether a date should be included in the year to date comparison, I used the formula where my date is in cell A1:
=IF((A1-DATE(YEAR(A1),1,1)+1)<=(TODAY()-DATE(YEAR(TODAY()),1,1)+1),1,0)
I’m looking for a way around the issue of the extra day added to leap years. In other words, after February 28th, the day count will always be off by one in a leap year, and trying to use Februrary 29th in a non-leap year will return an error.
I’d like to adjust this formula, but I’m open to using a different function & formula if it gets me the right results.
you can check any information about February, 29th. If an error occurs, you know its no leap year. Catch that error with =IFERROR(;).
Assuming a table structure like this:
A:Date | B:Value
----------------------
01/01/2016 | 0
01/01/2015 | 1
01/01/2014 | 2
01/01/2013 | 3
01/01/2012 | 4
Formula
To - for example - calculate the average of the previous four (excluding the current) years on January 1st (today is 01/01/2016):
=SUMPRODUCT(
(MONTH(A:A)=MONTH(compare))*
(DAY(A:A)=DAY(compare))*
(YEAR(A:A)>YEAR(compare)-5)*
(YEAR(A:A)<YEAR(compare))*
(B:B)
) / (
SUMPRODUCT(
(MONTH(A:A)=MONTH(compare))*
(DAY(A:A)=DAY(compare))*
(YEAR(A:A)>YEAR(compare)-5)*
(YEAR(A:A)<YEAR(compare))*
1
)
)
Result
For the above example, the result is 2.5
Explanation
To select only those rows representing the same month and day:
(MONTH(A:A)=MONTH(compare))*(DAY(A:A)=DAY(compare))
To select only those values from the previous 4 years (excluding the current):
(YEAR(A:A)>YEAR(compare)-5)*(YEAR(A:A)<YEAR(compare))*
The actual values we are interested in:
(B:B)
Divide by 4 for the average over the last four years. This assumes there is no missing data which might be an issue. You could use another SUMPRODUCT (replace B:B with 1) to count the number of resulting rows and divide by that number to handles this case. This seems to be rather slow, but it works.
Note
For performance reason you should not use A:A (a full column) in the formula, just use the actual range you need, which will likely be much faster.

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