计算范围内的特定天数

Question

How can I count the (fractional) count of specific day of the week in a range? For instance, if the range is from Monday, June 3 12:00 PM to Tuesday June 4 12:00 PM, and I want to count the number of Mondays, the formula would return the result 0.5.

I've already found a formula for the integer number of days:

=SUM(INT((WEEKDAY($B2-x)+$D2-$B2)/7))

where x is the day of the week of interest (1 to 7). Of course, it would need to be modified to return the aforementioned result. How would I do so?

Answer 1

You can get the total number of Mondays (including both start and end date) with this version (you don't need SUM)

=INT((WEEKDAY($B2-2)+INT($D2)-INT($B2))/7)

...and then do an adjustment to take into account the start/end days, eg

=INT((WEEKDAY($B2-2)+INT($D2)-INT($B2))/7)-IF(WEEKDAY($D2)=2,1-MOD($D2,1))-IF(WEEKDAY($B2)=2,MOD($B2,1))

I don't really recommend it (it's much more resource-hungry) but this version should give you the same result

=SUMPRODUCT((TEXT(B2+(ROW(INDIRECT("1:"&ROUND((D2-B2)*1440,0)))-0.5)/1440,"ddd")="mon")+0)/1440

It tests every minute within the date range to ascertain whether or not it falls on a Monday (assumes that you don't go down to seconds)