Array Formula for numbering similar nos (counting)

[noname]

Hi,

I have numbers in column A like this:
Col A
-----
1
1
1
1
2
2
2
3
3
3
3
3

I want a formula (probably an Array Formula) in Col B which will
number the similar numbers in this range. Like this:

Col A Col B
-------------
1 1
1 2
1 3
1 4
2 1
2 2
2 3
3 1
3 2
3 3
3 4
3 5

Has anyone done something like this?

 

[Pete_UK]

No need for an array formula. Just put this in B1:

=COUNTIF(A$1:A1,A1)

and copy down.

Hope this helps.

Pete