Count number of times an instructor has taught a class

Question

Howdy Folks, I'm using a lifeline to see if i can get some help for a question. I apologoze in advance, i know this is a numbers forum, but i am working with an excel spreadsheet and was hopng someone could give me a push in the right direction. i want to count how many times an instructor has taught a class based on dates. The spreadsheet is filled out via an applescript so the instructor's name appears with every student. I've been trying to use the count if formula in excel but i cant make it work. any suggestions? it should count james as 2 since he taught classes on two different dates, and nub as 1. all information is fictional and used for demo pruposes.

Answer 1

This will work for you... I hope:
I had to add three columns to your existing table, then crete a second table (on the right) to summarize:
The three columns can be anywhere but I added then right after column G
The table on the right in this example will have to be a new sheet in excel.  On a mac Numbers is free (If you have Mavericks) so maybe you want to try to download from the App store.
H2=IF(COUNTIF( $H$1:H1, F2&"-"&E2)=0, F2&"-"&E2, "")
this is shorthand for... select cell H2, then type (or copy and paste from here) the formula:
=IF(COUNTIF( $H$1:H1, F2&"-"&E2)=0, F2&"-"&E2, "")
I2=IF(H2="", "", MAX($I$1:I1)+1)
J2=IF(COUNTIF($F$1:F1,F2)>0, "", MAX($J$1:J1)+1)
select H2 thru J2, copy
select H2 thru the end of  column J
paste
In the new table (for Numbers) or sheet(in excel):
A2=IF((ROW()−2)<MAX(Table 2::J), OFFSET(Table 2::$F$2,MATCH(ROW()−1, Table 2::J,0), 0),"")
B2=IF(A2≠"", COUNTIFS(Table 2::F, A2, Table 2::I, ">0"), "")
select A2 and B2, copy
fill down as needed