# ARRAY.JOIN function

This article describes the formula syntax of the
ARRAY.JOIN function.

## Description

Return the concatenation of two arrays.

## Syntax

ARRAY.JOIN(array1, array2)

array1 |
is an array or handle to an array. |

array2 |
is an array. |

Join two arrays.
The shape of the returned array is determined by the shape of the first array.
If the first array is a single column then so is the result. If the first
array is a single row then so is the result.
If the first array has more than one row the resulting array has the same
number of columns as the first array. If the size of the second array
is not a multiple of the number of columns of the first array then
the last partial row is omitted.

If `array1`

is a handle then `array2`

is appended to
the associated in-memory array and the handle to the first array is returned.
If `array2`

is a handle and `array1`

is not,
then `array1`

is prepended to the
in-memory array and the handle for the second array is returned.
In this case the shape of the result is determined by the second
array as described above.

This function is useful for buffering data produced by Excel into memory. For example,
`ARRAY.TAKE(4, ARRAY.JOIN(RAND(), handle))`

returns a handle to (at most)
the last 4 values generated by `RAND()`

.
Use `ARRAY.TAKE(-4, ARRAY.JOIN(handle, RAND())`

to get the same items
in reverse order more efficiently.

## See Also

\ARRAY
, ARRAY.TAKE