How to write this function?

[Zilla]

Say I have the following

A B
1 2 10
2 4 5
3 2 20
4 2 30
5 4 11

How can I write a func. so if the cell values are equal,
for A col, it will add the values in corresponding B col,
then average the value out?

avg = SUM / #occur

So in may example, A1,A3 and A5 are all 2's so...
avg = 60 / 3 = 20

Again, A2 and A5 are both 4's so...
avg = 16 / 2 = 8

Thanks!

 

[Max]

One way ..
In C1: =SUMIF(A:A,A1,B:B)/COUNTIF(A:A,A1)
Copy down

 

[Guest]

=AVERAGE(IF($A$1:$A$100=2,$B$1:$B$100))

entered with Ctrl+Shift+Enter

 

[Zilla]

Ok thanks, I'll try this way...

One way ..
In C1: =SUMIF(A:A,A1,B:B)/COUNTIF(A:A,A1)
Copy down

 

[Zilla]

Thanks but this will be tedious since you hard-coded "2",
which is just an example value. So if I change "2" to "19",
I'd have to change it in ALL the formulas...

 

[Guest]

Change the 2 to a cell address

=AVERAGE(IF($A$1:$A$100=$Z$1,$B$1:$B$100))

 

[Max]

welcome. it should return what you're after.

 

[Max]

You could point Topper's array suggestion to the source cells in col A
Eg in C1, array-entered (press CTRL+SHIFT+ENTER):
=AVERAGE(IF($A$1:$A$100=A1,$B$1:$B$100))
Copy down (Adapt the ranges to suit before you copy down)

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