Need a formula . . .

Question

I am looking for a way to take a master list of names as shown in "Table 1" and automatically sort those marked entries into new tables which correspond to their categorization as shown in the "Red Group," "Blue Group," etc.
Of course, the check-boxes return a TRUE or FALSE according to whether they are checked. I am imagining something which functions similarly to the COUNTIF or SUMIF commands in that it would cycle through the list and grab only the names which correspond to the search criteria, e.g., "B2:B9=TRUE", and populate the new list accordingly.
Probably rudimentary for someone who does this for a living, but it is beyond my present knowledge. Thanks in advance for any help you can give.
BTW, Am using Numbers 3.5.2; OS 10.10.2, if it matters.
Thanks again,
Scott

Answer 1

Hello
As far as I can tell with Numbers v2, value of blank cell retrieved by formula is normally 0. You may concatenate it to "" to produce empty string instead of 0 but this way the result is always text and not number.
E.g.,
Red
A1 
A2  =IF(LEN($C2)>0,""&INDEX(Data::A,$C2,1),"")
A3  =IF(LEN($C3)>0,""&INDEX(Data::A,$C3,1),"")
A4  =IF(LEN($C4)>0,""&INDEX(Data::A,$C4,1),"")
A5  =IF(LEN($C5)>0,""&INDEX(Data::A,$C5,1),"")
B1 
B2  =IF(LEN($C2)>0,""&INDEX(Data::B,$C2,1),"")
B3  =IF(LEN($C3)>0,""&INDEX(Data::B,$C3,1),"")
B4  =IF(LEN($C4)>0,""&INDEX(Data::B,$C4,1),"")
B5  =IF(LEN($C5)>0,""&INDEX(Data::B,$C5,1),"")
C1  index
C2  =IFERROR(MATCH(TRUE,Data::C,0),0)
C3  =IFERROR(MATCH(TRUE,OFFSET(Data::C,C2,0,ROWS(Data::C)-C2,1),0)+C2,"")
C4  =IFERROR(MATCH(TRUE,OFFSET(Data::C,C3,0,ROWS(Data::C)-C3,1),0)+C3,"")
C5  =IFERROR(MATCH(TRUE,OFFSET(Data::C,C4,0,ROWS(Data::C)-C4,1),0)+C4,"")
As for blankness test, ISBLANK() returns false for cell which contains formula. LEN()=0 test would work.
E.g.,
Blankness Test
A1  isblank()
A2  =ISBLANK(Red::A2)
B1  len()=0
B2  =LEN(Red::A2)=0
Regards,
H