# `Errow`
[🔗](https://github.com/kuku/errow/blob/v0.1.0/lib/errow.ex#L1)

`Errow` - Zero-copy, Apache Arrow-compliant packed arrays for Elixir and the BEAM.

`Errow` provides columnar in-memory arrays backed by continuous BEAM binaries,
fully integrated with standard Elixir protocols (`Enumerable`, `Collectable`, `Access`),
and 100% byte-for-byte compliant with the **Apache Arrow Columnar Specification** and
**Arrow C Data Interface**.

## Modules
* `Errow.String`: UTF-8 variable-length string arrays (Arrow `Utf8` / VARCHAR).
* `Errow.Binary`: Opaque raw byte blob arrays (Arrow `Binary` / BLOB).
* `Errow.Numeric`: Fixed-width primitive arrays (`:s8`..`:s256`, `:u8`..`:u256`, `:f32`, `:f64`).
* `Errow.CData`: Exporters for Arrow C Data Interface (`ArrowArray` / `ArrowSchema` metadata and buffers).

## Quick Examples

### Strings & Comprehensions (`Collectable` + `Enumerable`)
    iex> arr = for name <- ["Elixir", "Arrow", "BEAM"], into: Errow.string() do
    ...>   String.upcase(name)
    ...> end
    iex> arr[0]
    "ELIXIR"
    iex> arr[-1]
    "BEAM"
    iex> arr[0..1]
    ["ELIXIR", "ARROW"]

### Numerics with 128-bit / 256-bit BigInt Support
    iex> num = Errow.numeric([10, 20, 30], :s32)
    iex> Enum.sum(num)
    60
    iex> put_in(num[1], 99)[1]
    99

### Zero-Copy Arrow Export
    iex> arr = Errow.string(["Elixir", "Arrow"])
    iex> schema = Errow.CData.export_schema(arr)
    iex> schema.format
    "u"
    iex> %{buffers: [_validity, _offsets, _data]} = Errow.CData.export_buffers(arr)

# `binary`

Creates a new empty `Errow.Binary` array.

# `binary`

Builds an `Errow.Binary` array from an enumerable.

# `f32`

Creates a 32-bit float array (`:f32`).

# `f32`

# `f64`

Creates a 64-bit float array (`:f64`).

# `f64`

# `join`

Joins string elements with the given separator.

# `max`

# `max`

Returns the maximum value in a numeric or string array.

# `mean`

Calculates the arithmetic mean of elements in a numeric array.

# `min`

# `min`

Returns the minimum value in a numeric or string array.

# `min_max`

Returns `{min, max}` in a single pass.

# `numeric`

Creates a new empty `Errow.Numeric` array of the given type (default `:s64`).

# `numeric`

Builds an `Errow.Numeric` array from an enumerable of numbers and optional `nil`s.

# `numeric_8`

Creates an 8-bit integer array (`:s8` by default, or `:u8`).
Usable directly in comprehensions: `into: Errow.numeric_8` or `into: Errow.numeric_8()`

# `numeric_8`

# `numeric_8`

# `numeric_16`

# `numeric_16`

# `numeric_16`

# `numeric_32`

# `numeric_32`

# `numeric_32`

# `numeric_64`

# `numeric_64`

# `numeric_64`

# `numeric_128`

# `numeric_128`

# `numeric_128`

# `numeric_256`

# `numeric_256`

# `numeric_256`

# `numeric_f32`

# `numeric_f32`

# `numeric_f64`

# `numeric_f64`

# `numeric_u8`

# `numeric_u8`

# `numeric_u16`

# `numeric_u16`

# `numeric_u32`

# `numeric_u32`

# `numeric_u64`

# `numeric_u64`

# `numeric_u128`

# `numeric_u128`

# `numeric_u256`

# `numeric_u256`

# `product`

Calculates the product of elements in a numeric array.

# `s8`

Creates an empty signed 8-bit integer array (`:s8`).
Usable directly in comprehensions: `into: Errow.s8` or `into: Errow.s8()`.

# `s8`

# `s16`

Creates a signed 16-bit integer array (`:s16`).

# `s16`

# `s32`

Creates a signed 32-bit integer array (`:s32`).

# `s32`

# `s64`

Creates a signed 64-bit integer array (`:s64`).

# `s64`

# `s128`

Creates a signed 128-bit integer array (`:s128`).

# `s128`

# `s256`

Creates a signed 256-bit integer array (`:s256`).

# `s256`

# `string`

Creates a new empty `Errow.String` array.

# `string`

Builds an `Errow.String` array from an enumerable.

# `sum`

Calculates the sum of elements in a numeric array.

# `u8`

Creates an empty unsigned 8-bit integer array (`:u8`).
Usable directly in comprehensions: `into: Errow.u8` or `into: Errow.u8()`.

# `u8`

# `u16`

Creates an unsigned 16-bit integer array (`:u16`).

# `u16`

# `u32`

Creates an unsigned 32-bit integer array (`:u32`).

# `u32`

# `u64`

Creates an unsigned 64-bit integer array (`:u64`).

# `u64`

# `u128`

Creates an unsigned 128-bit integer array (`:u128`).

# `u128`

# `u256`

Creates an unsigned 256-bit integer array (`:u256`).

# `u256`

---

*Consult [api-reference.md](api-reference.md) for complete listing*