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I have a table of data with many data repeating.
I have to sort the rows by random, however, without having identical names next to each other, like shown here:
How can I do that in Excel?
Perfect case for a recursive LAMBDA.
In Name Manager, define RandomSort as
=LAMBDA(ζ,
LET(
ξ, SORTBY(ζ, RANDARRAY(ROWS(ζ))),
λ, TAKE(ξ, , 1),
κ, SUMPRODUCT(N(DROP(λ, -1) = DROP(λ, 1))),
IF(κ = 0, ξ, RandomSort(ζ))
)
)
then enter
=RandomSort(A2:B8)
within the worksheet somewhere. Replace A2:B8 - which should be your data excluding the headers - as required.
If no solution is possible then you will receive a #NUM! error. I didn't get round to adding a clause to determine whether a certain combination of names has a solution or not.
This is just an attempt because the question might need clarification or more sample data to understand the actual scenario. The main idea is to generate a random list from the input, then distribute it evenly by names. This ensures no repetition of consecutive names, but this is not the only possible way of sorting (this problem may have multiple valid combinations), but this is a valid one. The solution is volatile (every time Excel recalculates, a new output is generated) because RANDARRAY is volatile function.
In cell D2, you can use the following formula:
=LET(rng, A2:B8, m, ROWS(rng), seq, SEQUENCE(m),
idx, SORTBY(seq, RANDARRAY(m,,1,m, TRUE)), rRng, INDEX(rng, idx,{1,2}),
names, INDEX(rRng,,1), nCnts, MAP(seq, LAMBDA(s, ROWS(FILTER(names,
(names=INDEX(names,s)) * (seq<=s))))), SORTBY(rRng, nCnts))
Here is the output:
Update
Looking at #JosWoolley approach. The generation of the random sorting can be simplified so that the resulting formula could be:
=LET(rng, A2:B8, m, ROWS(rng), seq, SEQUENCE(m), rRng,SORTBY(rng, RANDARRAY(m)),
names, TAKE(rRng,,1), nCnts, MAP(seq, LAMBDA(s, ROWS(FILTER(names,
(names=INDEX(names,s)) * (seq<=s))))), SORTBY(rRng, nCnts))
Explanation
LET function is used for easy reading and composition. The name idx represents a random sequence of the input index positions. The name rRng, represents the input rng, but sorted by random. This sorting doesn't ensure consecutive names are distinct.
In order to ensure consecutive names are not repeated, we enumerate (nCnts) repeated names. We use a MAP for that. This is a similar idea provided by #cybernetic.nomad in the comment section, but adapted for an array version (we cannot use COUNTIF because it requires a range). Finally, we use SORTBY with input argument by_array, the map result (nCnts), to ensure names are evenly distributed so no consecutive names will be the same. Every time Excel recalculate you will get an output with the names distributed evenly in a different way.
Not sure if it's worth posting this, but I might as well share the results of my research such as it is. The problem is similar to that of re-arranging the characters in a string so that no same characters are adjacent The method is just to insert whichever one of the remaining characters (names) has the highest frequency at this point and is not the same as the previous character, then reduce its frequency once it has been used. It's fairly easy to implement this in Excel, even in Excel 2019. So if the initial frequencies are in D2:D8 for convenience using Countif:
=COUNTIF(A$2:A$8,A2)
You can use this formula in (say) F2 and pull it down:
=INDEX(A$2:A$8,MATCH(MAX((D$2:D$8-COUNTIF(F$1:F1,A$2:A$8))*(A$2:A$8<>F1)),(D$2:D$8-COUNTIF(F$1:F1,A$2:A$8))*(A$2:A$8<>F1),0))
and similarly in G2 to get the ages:
=INDEX(B$2:B$8,MATCH(MAX((D$2:D$8-COUNTIF(F$1:F1,A$2:A$8))*(A$2:A$8<>F1)),(D$2:D$8-COUNTIF(F$1:F1,A$2:A$8))*(A$2:A$8<>F1),0))
I'm fairly sure this will always produce a correct result if one is possible.
HOWEVER there is no randomness built in to this method. You can see if I extend it to more data that in the first several rows the most common name simply alternates with the other two names:
Having said that, this is a bit of a worst case scenario (a lot of duplication) and it may not look too bad with real data, so it may be worth considering this approach along with the other two methods.
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$12),1)))))
Edit
If you have Excel/O365 with dynamic arrays and the FILTER function, you can greatly simplify the above to the normally entered:
=SUM(FILTER(Transactions[Out],Transactions[Category]=I12))
I have been trying to get this function to work but cant seem to get the correct result. What I am trying to accomplish is to Index Match Match a cell from the second table to the first table and evaluate the first set of coordinates, lets say (a,c) , with another set of coordinates (c,a). I will always be evaluating the inverse of each others coordinate. If all goes correctly, the two points in this example are -4 and 4. If the two coordiantes match eachothers inverse then True, otherwise False. I think I set up my function correctly but I cant seem to find the issue with it.
=(INDEX($B$2:$F$6,MATCH($A14,$A$2:$A$6,0),MATCH(B$13,$B$1:$F$1,0)))=(-(INDEX($B$2:$F$6,MATCH($A14,$B$1:$F$1,0),MATCH(B$13,$A$2:$A$6,0))))
Try this formula:
=B2=-INDEX($B$2:$F$6,MATCH(B$1,$B$1:$F$1,0),MATCH($A2,$A$2:$A$6,0))
I think you just mixed up your rows and columns. Also, you don't need the first INDEX, you can just refer to the cell
Example (note I changed one value just to make sure it is working):
If it is always a square matrix, and you don't mind entering it as a single array formula, you could use TRANSPOSE. Enter this in a 5 x 5 area and commit with ctrl+shift+enter:
=-B2:F6=TRANSPOSE(B2:F6)
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
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