Creating a dynamic repeating sequence of arrays

[ElRafaVaz33]

Hi Excel community,

I'm trying to find a way to create a dynamic array of repeating cells. I was attempting a similar technique on Google Sheets where you can use a Rept and TextJoin to create a string of the right number of elements, and then a Split function to separate them into rows.

However I haven't been able to find a way to do this in Excel; I get stumped on the split step. Would anyone have any suggestions on how to go about this? 

Here's a visual example of what I'm trying to achieve:

For reference I'm using Office 365 on a mac. Perhaps I am thinking about this problem in the wrong way. Any direction I could investigate would be really helpful.

Thanks!

[#2]

@ElRafaVaz33 

Sub names_array()

Dim i As Integer
Dim lngzeilemax As Integer
Dim z As Integer
Dim y As Integer

With Tabelle1

lngzeilemax = .Range("B" & .Rows.Count).End(xlUp).Row

For i = 3 To lngzeilemax * Cells(1, 2).Value

For z = 1 To Cells(1, 2).Value

Cells(z + y, 3).Value = Cells(i, 2).Value

Next z

y = y + Cells(1, 2).Value

Next i

End With

End Sub

Maybe with this code. You can click the button in cell E2 in the attached file to start the macro.

[#3 · Accepted solution]

@ElRafaVaz33 There are lots of possibilities.  Here is one:

=LET(in,F1:F6,rep,G1,s,SEQUENCE(ROWS(in)*rep,1,0),INDEX(in,QUOTIENT(s,rep)+1))

[#4]

@ElRafaVaz33 

An alternative could be Power Query like in the attached file.

[#5]

Presuming names in A1:A3:
=TOCOL(CHOOSECOLS(A1:A3,1,SEQUENCE(3,1,1,0)))

*TOCOL and CHOOSECOLS are available with Insider (beta channel).

[#6]

This is perfect, thank you! I'd never heard of the LET function, but reading on it, it looks super powerful.

For anyone reading this after me, here the source list is given from F1:F6 while G1 holds the number of repetitions.

[#7]

Thanks all for your answers! There definitely seems to be multiple ways to address this :)

[#8]

YES, LET() is SUPER awesome addition. If you don't know about it definitely learn. Also look into FILTER, SORT, UNIQUE, and then LAMBDA (which gets a little more complicated but even more powerful). Some great things happening in Excelverse

[#9]

@mtarler I've been trying to wrap my head around the LET function for this application. What if the OP wanted the list to repeat in an ABCABCABC fashion instead of AAABBBCCC? 

[#10]

@ElRafaVaz33 

With REDUCE

list - list of names to repeat

rep - number of times to repeat each

=REDUCE("Result",list,LAMBDA(a,v,VSTACK(a,EXPAND(v,rep,,v))))

[#11]

@farmerjenna @Patrick2788 gave a clever solution above but w/r to the original formula you can tweak it like this:

=LET(in,F1:F6,rep,G1,
     s,SEQUENCE(ROWS(in)*rep,1,0),
     INDEX(in,MOD(s-1,rep)+1))

so basically instead of using QUOTIENT which will give the integer value after dividing the number of rep (i.e. 1,1,1,2,2,2,3,3,3) I changed it to use MOD which will give the remainder after dividing so it gives (0,1,2,0,1,2,0,1,2) and then +1 to get index 1,2,3... 

another option using a variation on @Patrick2788 's first answer is:

=TOCOL(CHOOSE(SEQUENCE(1,6,1,0),A1:A3),,1)

in this case that very last 1 can be a 0 to create a,a,a,b,b,b,c,c,c or a 1 to make it a,b,c,a,b,c,...

btw the "6" is the number of repeates and the A1:A3 is the input range and this assumes a 'column' and if you have a row of input you probably have to swap the (1,6,1,0) to be (6,1,1,0)

In Patrick's actual version he used CHOOSECOLS so that would just get swapped with CHOOSEROWS

as I mentioned, lots of options :)

[#12]

D2#: =LET(a;A3:A5;b;B1;INDEX(a;SEQUENZ(ZEILEN(a)*b;;;1/b))) deutsch

D2#: =LET(a,A3:A5,b,B1,INDEX(a,SEQUENCE(ROWS(a)*b,,,1/b))) english (US)

makes it variable only on A3:A5 (and implicitly its count) and B1

[#13]

@ElRafaVaz33 

One more for the collection

=REDUCE(
    "Result",
    MAP(list, LAMBDA(v, LAMBDA(IF(SEQUENCE(n), v)))),
    LAMBDA(a,v, VSTACK(a, v()))
)

Close to what @Patrick2788 suggested.

[#14]

@ElRafaVaz33 

Sometimes the challenge is to know when to stop!

You could start with a basic kind of formula

= TOCOL(CHOOSECOLS(names, SEQUENCE(1,repeat,1,0)))

 but then, by the time you have used LET to remove the nesting and describe the intermediate steps, then wrapped the formula with a named LAMBDA to describe the operation and to list its arguments, you might finish up with

Repeatλ
= LET(
    index, SEQUENCE(1, repeat, 1, 0), 
    block, CHOOSECOLS(names, index), 
    TOCOL(block, , order)
  )

so the worksheet formulae are

= Repeatλ(names, repeat)

= Repeatλ(names, repeat, 1)

to give the results

respectively.

It all depends how much effort one is willing to commit to making things 'simple'!

[#15]

@farmerjenna 

=TOCOL(MAKEARRAY(ROWS(A1:A3),6,LAMBDA(r,c,INDEX(A1:A3,r))),,1)

Another alternative could be LAMBDA with MAKEARRAY. Range A1:A3 has values A, B and C in this example. 6 is the number of repeats in this example.

[#16]

Beautiful - simple & easy to understand.

[#17]

@fsdesloge and @ElRafaVaz33 With the functions now available in Excel for MS365, this can simply be achieved with TOCOL, IF and SEQUENCE:

=TOCOL(IF(SEQUENCE(,B1), A4:A6))

For a full explanation of this method, please see: https://techcommunity.microsoft.com/t5/excel/copy-array-n-times-with-excel-formula/m-p/4033181#M2178... 

[#18]

@djclements  - great - thanks!