Excel - Take Average of Monthly Data

问题:

I have a historical data set for commodity pricing. Throughout the data set, the data starts inputting prices on specific days, rather than the average of the entire month. In order to keep the flow of having only the average pricing for the months.

In the best case scenario, I would use an Averageif function, however, the data for each month doesn't display a consistent amount of days.

How can I automate this the process: If the month is the same as the previous row and different than the next row, calculate the average of the ^ rows until you hit the next month.

Here's a simple display of what I mean:

]1

回答1:

You can use a pivot table to get the output you want. It will also be neatly organized instead of having your averages mixed in with a mostly blank column. Photo below shows the set-up/output of a pivot table generated with random data.

回答2:

For a solution without pivot tables, you can use the following formula :
=AVERAGEIFS($B$1:$B$30;$A$1:$A$30;">="&(A1-DAY(A1)+1);$A$1:$A$30;"<="&EOMONTH(A1;0))

The above example is from cell C1, and can be copied down the entire list. The dates are in $A$1:$A$30 and the values in $B$1:$B$30. The first conditions test on the first day of the month (calculated as A1-DAY(A1)+1),and the second condition as last day of the month (calculated as EOMONTH(A1;0)

This will obviously put the average value of the month on each row, but will also work if your data is not sorted on date. If this is the case, and you only want to display one number per month in the column (as in your own example), you can add an additional IF statement wrapped around the formula:
=IF(EOMONTH(A2;0)=EOMONTH(A1;0);"";AVERAGEIFS($B$1:$B$30;$A$1:$A$30;">="&(A1-DAY(A1)+1);$A$1:$A$30;"<="&EOMONTH(A1;0)))
So it will display empty in all cells, except where the month changes.