Identify a subset of a range using TRUE statements - excel

Question

I am attempting to identify a subset of a range based on TRUE FALSE statements. An example is in the following chart below.
FALSE FALSE 1.21147
TRUE FALSE 1.20984
FALSE FALSE 1.21083
FALSE FALSE 1.210315
FALSE TRUE 1.21151
FALSE FALSE 1.21335
FALSE FALSE 1.213515
FALSE FALSE 1.212435
TRUE FALSE 1.212125
FALSE FALSE 1.21226
In this scenario I want a subset to be identified based on alternating TRUE statements. In the left side column the first TRUE statement would trigger the beginning of the subset an the TRUE statement in the second column would trigger the end of the subset. I then want to use a simple max function to identify the MAX in the third column. I would use an IF statement to determine whether or not the first TRUE statement is correct however, i am unable to figure out how to identify the subset of the range based on the TRUE statement in the second column. I also want to know whether or not this works from going from the top to the bottom if the statement could possible work going the bottom to the top. Any help would be most appreciated.

Answer 1

Part 1 can be done using a combination of MATCH, OFFSET and MAX
For this example I've assumed your data is located starting at cell A2.
For the sake of clarity I use some intermediate results in cells E1:E4. If you prefer a single formula, simply merge the intermediate formula into the final formula
Cell E2 = position of first TRUE in column A
=MATCH(TRUE,A2:A11,0)
Cell E3 = position of first TRUE in column B
=MATCH(TRUE,B2:B11,0)
Result formula, Max value in column C between the rows found in E2 and E3 (inclusive)
=MAX(OFFSET($C$1,E2,0,E3-E2+1,1))
Part 2 is more tricky: I don't think you can search up a range for a value. However, looking at your data it may be OK to search down for the second TRUE? If this is OK then:
Cell E4 = position of second TRUE in column A
=MATCH(TRUE,OFFSET(A2:A11,E2,0),0)
Or this, entered as an array formula (Insipred by Barry) which will get the last TRUE in the column
=MATCH(2, 1/(A2:A11=TRUE),1)
Result formula, Max value in column C between the rows found in E3 and E4 (inclusive)
=MAX(OFFSET($C$1,E3,0,E4+E2-E3+1,1))

Answer 2

your part about traversing the table from the bottom up confused me, and also don't know if you can have more than one subset, since you're penultimate row seems to be the opening of a new subset that is not closed. Anyway, hope that this helps. I'm assuming you don't want to use macros, in which case it would be trivial. What you can do is pad the top of the data set with an row that contains FALSE, FALSE, 0, 0, and add this formula to a fourth column starting with the first row of your set:
=IF(AND(NOT(A2),NOT(B2),OR(D1=0,AND(NOT(A1),B1))),0,C1)
That's assuming that your first row is row 2, and row 1 is used for the padding. A, B, and C are the three columns in your example, and D will print the value of the third column if it's within a subset, or zero if is not, so that you can easily calculate max() or whatever you want to do. I looks like this: