# `↓` — Split / Drop

Function. Keys: `Alt-j`. Ranks: `1` monadic, `1 ∞` dyadic

`↓Y` nests vectors along the last axis.

``` bpl
↓2 3⍴⍳6            ⍝ [[0 1 2] [3 4 5]]
```

`N↓Y` drops from the front; negative `N` drops from the end.

``` bpl
2↓1 2 3 4          ⍝ 3 4
¯2↓1 2 3 4         ⍝ 1 2
```

With [axes](quad-colon.qmd), `⍠K` selects the split axis or the drop
axes.

``` bpl
↓⍠0 (2 3⍴⍳6)       ⍝ [[0 3] [1 4] [2 5]]
```

Vector counts apply to successive leading axes. Overdrop gives an empty
axis.

``` bpl
1 1↓2 3⍴⍳6         ⍝ [4 5⋄]
5↓1 2              ⍝ ⍬
```

See [Mix / Take](up-arrow.qmd).

## Inverse

`↓⁻¹Y` mixes the items of `Y` into one array.

``` bpl
↓⁻¹[1 2;3 4]   ⍝ [1 2⋄3 4]
```