# `⍪` — Table / Catenate first

Function. Keys: `Alt-Minus ,`. Ranks: `∞` monadic, `∞ ∞` dyadic

`⍪Y` makes a matrix: first axis becomes rows, remaining axes become
columns.

``` bpl
⍪1 2 3             ⍝ 3 1⍴1 2 3
⍴⍪2 3 4⍴0          ⍝ [2 12]ₓ
```

`X⍪Y` joins on the first axis. `⍪⍠K` follows [catenate](comma.qmd).

``` bpl
1 2⍪3 4            ⍝ 1 2 3 4
```

## Inverse

`⍪⁻¹Y` gives the vector that a one-column matrix holds, and gives back
any other matrix. `X⍪⁻¹Y` removes the fixed major cells `X` from the
front of `Y`. With the right argument fixed, `(⍪↢X)⁻¹Y` removes them
from the end.

``` bpl
⍪⁻¹⍪1 2 3             ⍝ 1 2 3
[1 2]⍪⁻¹[1 2⋄3 4]   ⍝ [3 4⋄]
```