Returning Values to the Left of a VLOOKUP

Instead of using CHOOSE() with its general unfamiliarity for most and with some odd effects if not setting up a simple use, use INDEX() to create the ad hoc array used internally by the formula.

So the tip's formula that uses CHOOSE() adapted to using INDEX() would be: (data in, say, A1:E100, and lookup value in G1)

=VLOOKUP(G1, INDEX($A$1:$E$100,SEQUENCE(ROWS(A1:F5)), {4,1}), 2, false)

INDEX() returns an array of only the necessary columns, not the whole data table, with column 4 (D) first, then column 1 (A) second. So now your formula has a lookup array with the lookup column to the left of the result column and VLOOKUP() will function normally. Which in this case has the effect of "looking left."

MANY more people are good with using INDEX() than CHOOSE() (familiarity and comfort that one is doing things right), INDEX() has none of the flakiness with results that CHOOSE() can have (though to be fair, the flakiness happens only when giving it a several column array rather than single column arrays to do the choosing from, but then given a data table and lack of familiarity, that's just what a casual user of it would likely do (as long as one is being fair, eh?)), and creating dynamic ranges from other formulas' results in an INDEX() function is something done all the time, not so for CHOOSE().

More complex uses of VLOOKUP() can be accomodated as well, by adding columns in the INDEX() function. So for a VLOOKUP() desiring two results from the table (column A nd column E, say, output in that order) for a single lookup (G1) would use the following:

=VLOOKUP(G1, INDEX($A$1:$E$100,SEQUENCE(ROWS(A1:F5)),{4,1,5}), {2,3), false)

Note:

SEQUENCE(ROWS(A1:F5)) and ROW(1:5), either could be used, the latter being "old school" — but SEQUENCE() takes care of a couple flakiness issues with ROW() now that we have SPILL functionality.

Though it seems one should be able to use a zero or nothing at all for the row parameter, when passing an array constant like {4,1} to INDEX(), it requires the number of rows (or columns if passing an {array constant} to be explicitly specified. Even if one uses "{5}" instead of "5" to specify column 5, one must then also specify the rows explicitly. So that's a knock against the "familiarity" arguement as most people seem religious about being able to write something like "INDEX(array,,3)" rather than "INDEX(array,0,3)" and get pretty pathological about not having the two commas in a row. To be honest though, that's more a personal problem than a familiarity problem, so... (Which I honestly don't understand anyway: writing a "0" is just as "I'm a clever insider" or "cool-looking" as the two commas and has the advantage (for other users) of having a parameter in place, even if it is cryptic to the casual user but it's two commas or bust for the religious. Just strange.)

@Gary H: For your interest, here is a complete discussion of the CHOOSE function including VLOOKUP/CHOOSE: https://www.ablebits.com/office-addins-blog/2018/05/30/choose-function-excel-formula-examples/

The real take-away here is the use of the CHOOSE function in the formula:
=VLOOKUP(G1,CHOOSE({1,2},$D$1:$D$100,$A$1:$A$100),2,FALSE)
CHOOSE is not an obvious function (at least to me) to use if you are not familiar with arrays and their usage.

The web page https://www.contextures.com/excelchoosefunction.html is one of the few help pages that gives the example of using arrays for the index_num of the CHOOSE function.

The benefit of reading ExcelTips, besides solving people’s Excel problems, is learning of new solutions you didn’t even realize were possible.

You can use the Lookup and "you don’t need to sort " the data first.

Not only that, the Lookup version is expandable to allow "multi-column" lookups.

You just need to be aware of the following form
=LOOKUP(2,1/($C$1:$C$100=G1),$A$1:$A$100)

Now say Column G is product name & Column H is product colour (with C & D being the equivalent reference columns), you can now expand your formula to look at both.
=LOOKUP(2,1/(($C$1:$C$100=G1)*($D$1:$D$100=H1)),$A$1:$A$100)

If you want to see how this works I initially got it from here where how it works is explained:
https://www.contextures.com/excelfunctionlookup.html?awt_l=KPwMX&awt_m=3awuejWAuYrB3hJ
(Contextures - LOOKUP Function Examples)
Note: This is NOT entered in as an array formula eventhough it might looks a lot like one.

oops, my previous entry should have ended thus:
B4:B7 D1:D4
4 j
8 k
2 m
5 x

I proposed the following but it was not included in the Tip above:

A job for LOOKUP, assuming your col. 1 is sorted ascending. (& the 2 columns can start at diff. rows!)
Syntax: LOOKUP(search-value, search-vector, result-vector)
[the search-vector must be sorted ascending & the search value can use wildcards].
=LOOKUP("m",D1:D4,B4:B7) yields 2
B4:B7 D1:D4
4 j
8 k
2 m
5 x

What about the LOOKUP function? It may be outdated, but the Vector form (see Excel Help) has a very simple and understandable formula and works quite happily - as long as the search column is sorted into alphabetical/numerical order.