Pre-selected dependable lists in Excel - excel

Question

Excel coding gurus, i'd like someone to land me a hand in a following problem:
What I have:
I have an Excel 2019. Not the 365 edition.
And I have an Excel table with 2 columns. Column I contains list of people. And each person in the I column has the country of his/her origin denoted in the correspondent cell of H column.
For a better view check this picture, plz.
And I have two drop-down enabled cells (K4 and L4).
K4 holds the list of all countries, presented in H col.
And L4 is supposed to have a list of people, avaliable in the col I
Now, the question is:
How can I code those K4 and L4 cells, so that when in K4 cell I select a country, then in the drop down list of L4 cell I'd get the list of only those people from the I column that have their country of origin equal to the one in K4?
I feel like it is possible to be done with those array-returning functions but I just can't wrap my head around it all.

Answer 1

I have it working like this so far.
The functions necessary for this are INDEX, MATCH, IF, IFERROR, and COUNTIF, which are all available in Excel 2019.
The only thing I'm struggling with (without 365) is that I can't figure out how to remove the white space for the dynamic range.
The formula in column 'E' is to make a unique list of the 'Country' column:
=IFERROR(INDEX($H$2:$H$20,MATCH(0,COUNTIF($E$1:$E1,$H$2:$H$20),0)),"")
This formula must begin at least in row 2, as it needs an empty space above it.
Column F is a similarly unique list of column I, but is dynamic based on the value in K4: *Now updated, see edit below
=IFERROR(INDEX($I$2:$I$20,MATCH(0,IF($K$4=$H$2:$H$20,COUNTIF($F$1:$F1,$I$2:$I$20),""),0)),"")
The validation in K4 is based on column E, and the validation in L4 is based on column F.
As I said, without O365 I can't figure out how to remove the white space, but this should at least work for you.
EDIT: I have had another look at this and figured out the whitespace issue:
Data validation for L4:
=INDIRECT("F2:"&"F"&(COUNTA(F:F)-COUNTIF(F:F," ")+1))
As a bonus, the data validation for K4 can be similar, in case you want to expand column H to include more entries:
=INDIRECT("E2:"&"E"&(COUNTA(E:E)-COUNTIF(E:E," ")+1))
This creates a list from F2 (which will always be our first value) and will expand dynamically as far down as column F has data, given that we change the formula in F2 to be:
=IFERROR(INDEX($I$2:$I$20,MATCH(0,IF($K$4=$H$2:$H$20,COUNTIF($F$1:$F1,$I$2:$I$20),""),0))," ")
Note that the character in the IFERROR of this formula and the COUNTIF of the previous is not a space, it's the character from Alt+255.
As a final nicety, adding some conditional formatting to cell L4 will make it so that selecting data in L4, and then changing the value of K4 (so that L4 is no longer valid) will return whitespace - which is really white text on a white background.
Conditional format formula for L4:
=NOT(IFERROR(ISNUMBER(SEARCH($L$4,TEXTJOIN(" ",1,F:F))),FALSE))

Answer 2

The following is my elaboration on #RGilchrist's answer that he presented above. His was the main idea thus all the credit goes to him too.
The functions, needed for this are INDEX, MATCH, IF, IFERROR, and COUNTIF, which are all available in Excel 2019.
The formula in column 'E' is to make a unique list of the 'Country' column:
=IFERROR(INDEX($H$2:$H$17;MATCH(0;COUNTIF($E$1:$E1;$H$2:$H$17);0));"")
For example, on the pic you can see a formula of the cell E2.
Some comments on this formula:
it should be entered into the cell by Ctrl+Shift+Enter as it is an array formula. And you can see that it is wrapped into curly brackets {}.
the formula needs to have at least 1 cell above it. In this case it is E1.
As you see on the picture - I've deliberately made my dataset sparce, not dence (it has empty rows). To work around having zero in the resultset one has to place 0 to the E1 cell.
on the picture my dataset is colored. That hints the fact that I've announced the dataset as a table. This would allow for some neat features like auto extending of the table should I add more rows to it. And that provides for some functionally neat addressing of the column in the dataset. In my locale the table-addressed following formula would be this:
=IFERROR(INDEX(Tab_1[Стовпець1];MATCH(0;COUNTIF($E$1:$E2;Tab_1[Стовпець1]);0));"") where Tab_1 is the name of the table I've announced. And [Стовпець1] is a name of the column in the table.
Column F is a similarly unique list of column I, but is dynamic based on the value in K4: =IFERROR(INDEX($I$2:$I$20,MATCH(0,IF($K$4=$H$2:$H$20,COUNTIF($F$1:$F1,$I$2:$I$20),""),0)),"")
All comments to previous formula are applicable to this one as well.
The data validation in K4 is based on column E, and the validation in L4 is based on column F. But in order to overcome empty space problem in resulting dropdown list the data validation should be based on a formula that uses OFFSET function.
So the data validation source for K4 would be
=OFFSET($E$2;;;COUNTIF($E$2:$E$10;"?*"))
The relevant screenshot is in my locale but the general interface should be familiar.