Stack multiple columns into one

Question

I want to do a simple task but somehow I'm unable to do it. Assume that I have one column like:

a
z
e
r
t

How can I create a new column with the same value twice with the following result:

a
a
z
z
e
e
r
r
t
t

I've already tried to double my column and do something like :

=TRANSPOSE(SPLIT(JOIN(";",A:A,B:B),";"))

but it creates:

a
z
e
r
t
a
z
e
r
t

I get inspired by this answer so far.

Answer 1

Try this:

=SORT({A1:A5;A1:A5})

Here we use:

• sort
• {} to combine data

---

Accounting your comment, then you may use this formula:

=QUERY(SORT(ArrayFormula({row(A1:A5),A1:A5;row(A1:A5),A1:A5})),"select Col2")

The idea is to use additional column of data with number of row, then sort by row, then query to get only values.

---

And join→split method will do the same: =TRANSPOSE(SPLIT(JOIN(",",ARRAYFORMULA(CONCAT(A1:A5&",",A1:A5))),","))

Here we use range only two times, so this is easier to use. Also see Concat + ArrayFormula sample.