How to compare 2 arrays with unequal numbers of elements in Excel - excel

In an Excel array formula, I would like to test each element of one array against each element of a second array, when the 2 arrays do NOT have the same number of elements. Simplified right down, this scenario could be represented by:
=SUMPRODUCT({1,2,3,4,5}={1,2})
NB - in my real world scenario these arrays are calculated from various prior steps.
Using the above example, I would want a result of {TRUE,TRUE,FALSE,FALSE,FALSE}. What I get is {TRUE,TRUE,#N/A,#N/A,#N/A}.
It's clear that, when there's more than 1 value being tested for, Excel wants equal numbers of elements in the 2 arrays; when there isn't, the #N/A error fills in the blanks.
I've considered writing a UDF to achieve what I want, and I'm pretty sure my coding skills are up to creating something like:
=ArrayCompare({1,2,3,4,5},"=",{1,2})
But I'd much rather do this using native functionality if it's not too cumbersome...
So, simple question; can an array formula be constructed to do what I'm after?
Thanks peeps!

Using MATCH function is probably the best way.....but if you actually want to compare every element in one array with another array in a direct comparison then one should be a "column" and one a "row", e.g.
=SUMPRODUCT(({1,2,3,4,5}={1;4})+0)
Note the semi-colon separator in the second array
If you can't actually change the column/row designation then TRANSPOSE can be used, i.e.
=SUMPRODUCT(({1,2,3,4,5}=TRANSPOSE({1,4}))+0)
You may not get the required results if the arrays contain duplicates because then you will get some double-counting, e.g. with this formula
=SUMPRODUCT(({1,1,1,1,1}={1;1})+0)
the result is 10 because there are 5x2 comparisons and they are all TRUE

Maybe:
{=IF(ISERROR(MATCH({1,2,3,4,5},{1,2},0)),FALSE,TRUE)}

If the second array is a subset of the first array, same order, and starting at position 1 then you can use this array formula for equivalence testing:
=IFERROR(IF({1,2,3,4,5}={1,2},TRUE),FALSE)
For non equivalence just swap the FALSE and TRUE
=IFERROR(IF({1,2,3,4,5}={1,2},FALSE),TRUE)
You can then use this in other formulas just as an array:
However if the arrays are not in order, as in this example:
{1,2,3,4,5},{1,4,5}
Then you have to use MATCH. However all you need is to surround the match with an ISNUMBER like so:
Equivalence test:
=ISNUMBER(MATCH({1,2,3,4,5},{1,4,5},0))
Non Equivalence test:
=NOT(ISNUMBER(MATCH({1,2,3,4,5},{1,4,5},0)))
Remember all array formulas are entered with ctrl + shift + enter

Related

Excel formula to sum an array of items from a lookup list

I'm trying to make my monthly transaction spreadsheet less work-intensive but I'm running up against problems outputting my category lookups as an array. Right now I have a table with all my monthly transactions and I want to create another table with monthly running totals. What I've been doing is manually summing each entry from each category, but I'd love to automate the process. Here's what I have:
=SUM(INDEX(Transactions[Out], N(IF(1,MATCH(I12,Transactions[Category],FALSE)))))
I've also tried using AGGREGATE in place of SUM but it still only returns the first value in the category. The N(IF()) was supposed to force INDEX to return all the matches as an array, but it's not working. I found that trick online, with no explanation of why it works, so I really don't know how to fix it. Any ideas?
Just in case anyone ever looks at this thread in the future, I was able to find a simpler solution to my problem once I implemented the Transactions[Category]=I12 method. SUM, itself will take an array as an argument, so all I had to do was form an array of the values I wanted to keep from Transactions[Out] range. I did this by adjusting the method Ron described above, but instead of using 1/(Transactions[Category]=I12 I used 1/IF(Transactions[Category]=I12, 1,1000) and surrounded that by a FLOOR(*resulting array*, .01) which rounded all the thousandth's down to zero and didn't yield any #DIV/0! errors.
Then! I realized that the simplest way to get the actual numbers I wanted, rather than messing with INDEX or AGGREGATE, was to multiply the range Transactions[Out] by the binary array from the IF test. Since the range is a table, I know they will always be the same size. And SUM automatically multiplies element by element and then adds for operations like this.
(The result is a "CSE" formula, which I guess isn't everyone's favorite. I'm still not 100% clear on what it means: just that it outputs data in a single cell, rather than over multiple cells. But in this context, SUM should only output a single number, so I'm not sure why I need CSE... A problem for another day!)
In your IF, the value_if_true clause needs to return an array of the desired row numbers from the array.
MATCH does not return an array of values; it only returns a single value which, with the FALSE parameter, will be the first value. That's why INDEX is only returning the first value.
One way to return an array of values:
Transactions[Category]=I12
will return an array of {TRUE,FALSE,FALSE,TRUE,...} depending on if it matches.
You can then multiply that by the Row number to get the relevant row on the worksheet.
Since you are using a table, to obtain the row number in the data body array, you have to subtract the row number of the Header row.
But now we are going to have an array which includes 0's for the non-matching entries, which is not good for us as a row number argument for the INDEX function.
So we get rid of that by using the AGGREGATE function with the ignore errors argument set after we do change the equality test to 1/(Transactions[Category]=I12) which will create DIV/0 errors for the non-matchers.
Putting it all together
=SUM(INDEX(Transactions[Out],AGGREGATE(15,6,1/(Transactions[Category]=I12)*ROW(Transactions)-ROW(Transactions[#Headers]),ROW(INDIRECT("1:"&COUNTIF(Transactions[Category],$I$12))))))
You may need to enter this with CSE depending on your version of Excel.
Also, if you have a lot of these formulas, you may want to change the k argument for AGGREGATE to use the INDEX function (non-volatile) instead of the volatile INDIRECT function.
=SUM(INDEX(Transactions[Out],AGGREGATE(15,6,1/(Transactions[Category]=I12)*ROW(Transactions)-ROW(Transactions[#Headers]),ROW(INDEX($A:$A,1,1):INDEX($A:$A,COUNTIF(Transactions[Category],$I$12),1)))))
Edit
If you have Excel/O365 with dynamic arrays and the FILTER function, you can greatly simplify the above to the normally entered:
=SUM(FILTER(Transactions[Out],Transactions[Category]=I12))

Comparing two arrays - Horizontal vs Vertical

What is the case
I'm trying to compare two arrays. For simplicity sake let's assume we want to know how often the values of one array exist in the other array.
My referenced/lookup array data sits in A1:A3
Apple
Lemon
Pear
My search array is NOT in the worksheet, but written {"Apple","Pear"}
Problem
So to know how often our search values exists in the lookuparray we can apply a formula like:
{=SUMPRODUCT(--(range1=range2))}
However, {=SUMPRODUCT(--({"Apple","Pear"}=A1:A3))} produces an error. In other words the lookup array wasn't working as expected.
What did work was using TRANSPOSE() function to create a horizontal array from my data first using {=SUMPRODUCT(--({"Apple","Pear"}=TRANSPOSE(A1:A3)))} resulting in the correct answer of 2!
It seems as though my typed array is automatically handled as an horizontal array, and my data obviously was originally vertical.
To test my hypotheses I tried another formula:
{=SUMPRODUCT(--({"Apple","Pear"}={"Apple","Lemon","Pear"}))}
Both are typed arrays, so with above logic it would both be horizontal arrays, perfectly able to work without using TRANSPOSE(), however this returns an error! #N/A
Again {=SUMPRODUCT(--({"Apple","Pear"}=TRANSPOSE({"Apple","Lemon","Pear"})))} gave a correct answer of 2.
Question
Can someone please explain to me:
The reasoning why horizontal can't be compared to vertical arrays.
Why a typed array would automatically be handled as horizontal
Why in my test of the hypotheses the second typed array was handled as vertical.
I'm really curious, and would also be happy to be linked to appropriate documentation as so far I have not been able to find any.
This might be an easy one to answer, though I can't seem to get my head around the logic.
Can someone please explain to me:
The reasoning why horizontal can't be compared to vertical arrays.
This is actually possible, and you can also compare horizontal arrays with other horizontal arrays.
The reason you have been getting the error is because of the mismatch in the length of the array. Consider the following arrays:
Doing =SUMPRODUCT(--(B3:D3=F3:G3)) is the same (on excel's english version, I'm not 100% sure on the delimiters on other versions) as =SUMPRODUCT(--({"Apple","Lemon","Pear"}={"Apple","Pear"})) and results in =SUMPRODUCT(--(Apple=Apple, Lemon=Pear, Pear=???)), that is the nth element of the first array is compared to the nth element of the second array, and if there is nothing to match --the 3rd element in the 1st array is Pear but there is no 3rd element for the 2nd array-- then you get N/A.
When you compare two arrays, one vertical and one horizontal, excel actually 'expands' the final array. Consider the following (1row x 3col and 2row x 1col):
Doing =SUMPRODUCT(--(B3:D3=F3:F4)) is the same as =SUMPRODUCT(--({"Apple","Lemon","Pear"}={"Apple";"Pear"})) and results in =SUMPRODUCT(--(Apple=Apple, Lemon=Apple, Pear=Apple; Apple=Pear, Lemon=Pear, Pear=Pear)). Basically it feels like Excel expanded the two arrays like this (3col x 2row):
This 'expansion' only happens when one array is 1 row high and the other is 1 column wide I believe, so if you take arrays that have something different, then excel will go back to trying to compare an element with 'nothing' to give N/A (you can use the Evaluate Formula feature under Formula tab to help):
So essentially excel is getting something a bit similar to this, where the first array is multiplied to the second array, giving the result array:
But since the last row and last column involve blanks, you get N/A there.
Why a typed array would automatically be handled as horizontal
In your question, it would seem that , delimit rows, so with =SUMPRODUCT(--({"Apple","Pear"}=A1:A3)) you are observing similar to the comparison of two rows in my first example, while with =SUMPRODUCT(--({"Apple","Pear"}=TRANSPOSE(A1:A3))), you are getting the 'expansion' occurring.
As stated in the comments, on the English version of excel, , delimits columns and ; delimits rows, as can be observed in this simple example where I supply an array with 2 rows and 3 columns, excel shows {0,0,0;0,0,0}:
Why in my test of the hypotheses the second typed array was handled as vertical.
TRANSPOSE simply switches an array from vertical to horizontal (and vice versa), but depending on what you are trying to do, you'll get different results as per the first part of my answer, so you'll either have N/A when excel cannot match an item of an array with another item of the other array, or 'expansion' of the two arrays that results in a bigger array.

Sum all rows when at least one row meets the criteria

I have a database as follows:
I am having issues trying to sum all the quantities by groups when the “Included” flag is Y for at least one of the groups; that is: if there’s a Y on at least one row from group 3 , sum all the rows from group 3, regardless if the rest are not included.
The output should be like this:
Thanks!
You're going to need to use an array function to solve this one. To enter and array function, type a function as you normally would then press Ctrl+Shift+Enter instead just Enter. (Apple Keyboards differ, but I don't have Apple.)
I'll explain how I put the function together, then bring it all together in the end.
First, I wanted an array of group numbers that have at least one "Y" in the Included column. That array is created by IF(B2:B14="Y",A2:A14,0). The result would be {0,0,0,0,0,0,3,...etc} in the sample case.
Next, I flag every group row that has an entry in the list of group numbers using the MATCH(A2:A14,IF(B2:B14="Y",A2:A14,0),0) function.
Since that uses an exact match, it will create an error when there is no match. ISERROR(MATCH(A2:A14,IF(B2:B14="Y",A2:A14,0),0)) gives me a true when there is not a match and a false when there is, so I negate it. NOT(ISERROR(MATCH(A2:A14,IF(B2:B14="Y",A2:A14,0),0)))
Another IF converts this to a 1 or a 0.
IF(NOT(ISERROR(MATCH(A2:A14,IF(B2:B14="Y",A2:A14,0),0))),1,0)
Finally, I bring it together with the Quantity using a SUMPRODUCT:
=SUMPRODUCT(C2:C14,IF(NOT(ISERROR(MATCH(A2:A14,IF(B2:B14="Y",A2:A14,0),0))),1,0))
Again, remember to Ctrl+Shift+Enter to make this work.
Tested in Excel 2013 and it works fine.

Multiple arrays within multiple arrays

I have multiple lookup values that I am trying to match across multiple arrays. I would like to match one of those lookup values across several arrays within the same match but I keep getting "#VALUE" or "#N/A".
Current formula I try to use is below simplified for ease of reading.
=INDEX($I$2:$I$10,MATCH(A2&B2&C2,$D$2:$D$10&OR($E$2:$E$10,$F$2:$F$10)&$G$2:$G$10,0))
In this case, I am trying to match B2 either in $E$2:$E$10 or $F$2:$F$10. What am I doing wrong?
Thanks in advance!
At first: You misinterpret the OR function. OR needs boolean values as parameters. And it will not return arrays of values, even not boolean values. It will return either TRUE or FALSE.
At second: Even if OR would work as you seem to think, MATCH needs an one dimensional lookup_array, a row vector or a column vector. It can't work with two dimensional matrices like {$D$2&$E$2&$G$2 , $D$2&$F$2&$G$2 ; $D$3&$E$3&$G$3 , $D$3&$F$3&$G$3 ; ...}
So simplest solution with your example would be to have one INDEX MATCH combination each possible lookup_array:
{=IFERROR(INDEX($I$2:$I$10,MATCH(A2&B2&C2,$D$2:$D$10&$E$2:$E$10&$G$2:$G$10,0)),INDEX($I$2:$I$10,MATCH(A2&B2&C2,$D$2:$D$10&$F$2:$F$10&$G$2:$G$10,0)))}
Or, if you really need this the way you seem to think your formula should work, then you can't use MATCH and need calculate the row number on other way. For example like so:
{=INDEX($I$2:$I$10,MIN(IF(A2&B2&C2=$D$2:$D$10&T(OFFSET($E$2,ROW($2:$10)-2,{0,1}))&$G$2:$G$10,ROW($2:$10)-1,ROWS($D$2:$D$10)+1)))}
The T is used assuming the values in A2:G10 are text values. If they are numeric, N must be used instead.

nested excel functions with conditional logic

Just getting started in Excel and I was working with a database extract where I need to count values only if items in another column are unique.
So- below is my starting point:
=SUMPRODUCT(COUNTIF(C3:C94735,{"Sharable Content Object Reference Model 1.2","Authored SCORM/AICC content","Authored External Web Content"}))
what i'd like to figure out is the syntax to do something like this-
=sumproduct (Countif range1 criteria..., where range2 criteria="is unique value")
Am I getting this right? The syntax is a bit confusing, and I'm not sure I've chosen the right functions for the task.
I just had to solve this same problem a week ago.
This method works even when you can't always sort on the grouping column (J in your case). If you can keep the data sorted, #MikeD 's solution will scale better.
Firstly, do you know the FREQUENCY trick for counting unique numbers? FREQUENCY is designed to create histograms. It takes two arrays, 'data' and 'bins'. It sorts 'bins', then creates an output array that's one longer than 'bins'. Then it takes each value in 'data' and determines which bin it belongs in, incrementing the output array accordingly. It returns the array. Here's the important part: If a value appears in 'bins' more than once, any 'data' value meant for that bin goes in the first occurrence. The trick is to use the same array for both 'data' and 'bins'. Think it through, and you'll see that there's one non-zero value in the output for each unique number in the input. Note that it only counts numbers.
In short, I use this:
=SUM(SIGN(FREQUENCY(<array>,<array>)))
to count unique numeric values in <array>
From this, we just need to construct arrays containing numbers where appropriate and text elsewhere.
In the example below, I'm counting unique days when the color is red and the fruit is citrus:
This is my conditional array, returning 1 or true for the rows I'm interested in:
($A$2:$A$10="red")*ISNUMBER(MATCH($B$2:$B$10,{"orange","grapefruit","lemon","lime"},0))
Note that this requires ctrl-shift-enter to be used as an array formula.
Since the value I'm grouping by for uniqueness is text (as is yours), I need to convert it to numeric. I use:
MATCH($C$2:$C$10,$C$2:$C$10,0)
Note that this also requires ctrl-shift-enter
So, this is the array of numeric values within which I'm looking for uniqueness:
IF(($A$2:$A$10="red")*ISNUMBER(MATCH($B$2:$B$10,{"orange","grapefruit","lemon","lime"},0)),MATCH($C$2:$C$10,$C$2:$C$10,0),"")
Now I plug that into my uniqueness counter:
=SUM(SIGN(FREQUENCY(<array>,<array>)))
to get:
=SUM(SIGN(FREQUENCY(
IF(($A$2:$A$10="red")*ISNUMBER(MATCH($B$2:$B$10,{"orange","grapefruit","lemon","lime"},0)),MATCH($C$2:$C$10,$C$2:$C$10,0),""),
IF(($A$2:$A$10="red")*ISNUMBER(MATCH($B$2:$B$10,{"orange","grapefruit","lemon","lime"},0)),MATCH($C$2:$C$10,$C$2:$C$10,0),"")
)))
Again, this must be entered as an array formula using ctrl-shift-enter. Replacing SUM with SUMPRODUCT will not cut it.
In your example, you'd use something like:
=SUM(SIGN(FREQUENCY(
IF(ISNUMBER(MATCH($C$3:$C$94735,{"Sharable Content Object Reference Model 1.2","Authored SCORM/AICC content","Authored External Web Content"},0)),MATCH($J$3:$J$94735,$J$3:$J$94735,0),""),
IF(ISNUMBER(MATCH($C$3:$C$94735,{"Sharable Content Object Reference Model 1.2","Authored SCORM/AICC content","Authored External Web Content"},0)),MATCH($J$3:$J$94735,$J$3:$J$94735,0),"")
)))
I'll note, though, that scaling might be a problem on data sets as large as yours. I tested it on larger data sets, and it was fairly fast on the order of 10k rows, but really slow on the order of 100k rows, such as yours. The internal arrays are plenty fast, but the FREQUENCY function slows down. I'm not sure, but I'd guess it's between O(n log n) and O(n^2) depending on how the sort is implemented.
Maybe this doesn't matter - none of this is volatile, so it'll just need to calculate once upon refreshing the data. If the column data is changing, though, this could be painful.
Asuming the source data is sorted by the key value [A], start with determining the occurence of the key column
B2: =IF(A2=A1;B1+1;1)
Next determine a group sum
C2: =SUMIF($A$2:$A$9;A2;$B$2:$B$9)
A key is unique if its group sum is exactly 1
D2: =(C2=1)
To count records which match a certain criterium AND are unique, include column D in a =IF(AND(D2, [yourcondition];1;0) and sum this column
Another option is to asume a key unique within a sorted list if it is unequal to both its predecessor and successor, so you could find the unique records like
E2: =AND(A2<>A1;A2<>A3)
G2: =IF(AND(E2;F2="this");1;0)
E and G can of course be combined into one single formula (not sure though if that helps ...)
G2(2): =IF(AND(AND(A2<>A1;A2<>A3);F2="this");1;0)
resolving unnecessarily nested AND's:
G2(3): =IF(AND(A2<>A1;A2<>A3;F2="this");1;0)
all formulas in row 2 should be copied down to the end of the list

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