defmodule Aja.Vector do
# TODO remove doc hack when stop supporting 1.10
plusplusplus_doc = ~S"""
## Convenience [`+++/2`](`Aja.+++/2`) operator
The `Aja.+++/2` operator can make appending to a vector more compact by aliasing `Aja.Vector.concat/2`:
iex> import Aja
iex> vec([1, 2, 3]) +++ vec([4, 5])
vec([1, 2, 3, 4, 5])
"""
@moduledoc ~s"""
Fast persistent vector with efficient appends and random access.
Persistent vectors have been introduced by Clojure as an efficient alternative to lists.
Many operations for `Aja.Vector` run in effective constant time (length, random access, appends...),
unlike linked lists for which most operations run in linear time.
Functions that need to go through the whole collection like `map/2` or `foldl/3` are as often fast as
their list equivalents, or sometimes even slightly faster.
Vectors also use less memory than lists for "big" collections (see the [Memory usage section](#module-memory-usage)).
Make sure to read the [Efficiency guide section](#module-efficiency-guide) to get the best performance
out of vectors.
Erlang's [`:array`](`:array`) module offer similar functionalities.
However `Aja.Vector`:
- is a better Elixir citizen: pipe-friendliness, `Access` behaviour, `Enum` / `Inspect` / `Collectable` protocols
- is heavily optimized and should offer higher performance in most use cases, especially "loops" like `map/2` / `to_list/1` / `foldl/3`
- mirrors most of the `Enum` module API (together with `Aja.Enum`) with highly optimized versions for vectors (`Aja.Enum.join/1`, `Aja.Enum.sum/1`, `Aja.Enum.random/1`...)
- supports negative indexing (e.g. `-1` corresponds to the last element)
- optionally implements the `Jason.Encoder` protocol if `Jason` is installed
Note: most of the design is inspired by
[this series of blog posts](https://hypirion.com/musings/understanding-persistent-vector-pt-1) describing
the Clojure implementation, but a branching factor of `16 = 2 ^ 4` has been picked instead of `32 = 2 ^ 5`.
This choice was made following performance benchmarking that showed better overall performance
for this particular implementation.
## Examples
iex> vector = Aja.Vector.new(1..10)
vec([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
iex> Aja.Vector.append(vector, :foo)
vec([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, :foo])
iex> vector[3]
4
iex> Aja.Vector.replace_at(vector, -1, :bar)
vec([1, 2, 3, 4, 5, 6, 7, 8, 9, :bar])
iex> 3 in vector
true
## Access behaviour
`Aja.Vector` implements the `Access` behaviour.
iex> vector = Aja.Vector.new(1..10)
iex> vector[3]
4
iex> put_in(vector[5], :foo)
vec([1, 2, 3, 4, 5, :foo, 7, 8, 9, 10])
iex> {9, updated} = pop_in(vector[8]); updated
vec([1, 2, 3, 4, 5, 6, 7, 8, 10])
## Convenience [`vec/1`](`Aja.vec/1`) and [`vec_size/1`](`Aja.vec_size/1`) macros
The `Aja.Vector` module can be used without any macro.
The `Aja.vec/1` macro does however provide some syntactic sugar to make
it more convenient to work with vectors of known size, namely:
- pattern match on elements for vectors of known size
- construct new vectors of known size faster, by generating the AST at compile time
Examples:
iex> import Aja
iex> vec([1, 2, 3])
vec([1, 2, 3])
iex> vec([1, 2, var, _, _, _]) = Aja.Vector.new(1..6); var
3
iex> vec(first ||| last) = Aja.Vector.new(0..99_999); {first, last}
{0, 99999}
The `Aja.vec_size/1` macro can be used in guards:
iex> import Aja
iex> match?(v when vec_size(v) > 99, Aja.Vector.new(1..100))
true
#{if Version.compare(System.version(), "1.11.0") != :lt do
plusplusplus_doc
end}
## Pattern-matching and opaque type
An `Aja.Vector` is represented internally using the `%Aja.Vector{}` struct. This struct
can be used whenever there's a need to pattern match on something being an `Aja.Vector`:
iex> match?(%Aja.Vector{}, Aja.Vector.new())
true
Note, however, that `Aja.Vector` should be considered an opaque type: its struct internal fields
must not be accessed directly (even if not enforced by dialyzer because of pattern-matching).
As discussed in the previous section, [`vec/1`](`Aja.vec/1`) makes it
possible to pattern match on size and elements as well as checking the type.
## Memory usage
Vectors have a small overhead over lists for smaller collections, but are using
far less memory for bigger collections:
iex> memory_for = fn n -> [Enum.to_list(1..n), Aja.Vector.new(1..n)] |> Enum.map(&:erts_debug.size/1) end
iex> memory_for.(1)
[2, 32]
iex> memory_for.(10)
[20, 32]
iex> memory_for.(100)
[200, 151]
iex> memory_for.(10_000)
[20000, 11371]
If you need to work with vectors containing mostly the same value, `Aja.Vector.duplicate/2`
is highly efficient both in time and memory (logarithmic).
It minimizes the number of actual copies and reuses the same nested structures under the hood:
iex> Aja.Vector.duplicate(0, 10_000) |> :erts_debug.size()
117
iex> Aja.Vector.duplicate(0, 10_000) |> :erts_debug.flat_size() # when shared over processes / ETS
11371
Even a 1B x 1B matrix of the same element costs virtually nothing!
big_n = 1_000_000_000
0 |> Aja.Vector.duplicate(big_n) |> Aja.Vector.duplicate(big_n) |> :erts_debug.size()
539
## Efficiency guide
If you are using vectors and not lists, chances are that you care about
performance. Here are a couple notes about how to use vectors in an optimal
way. Most functions from this module are highly efficient, those that are not
will indicate it in their documentation.
But remember the golden rule: **in case of doubt, always benchmark**.
### Avoid prepending
Appending is very efficient, but prepending is highly inefficient since the
whole array needs to be reconstructed.
**DON'T**
Aja.Vector.prepend(vector, :foo)
**DO**
[:foo | list] # use lists
Aja.Vector.append(vector, :foo)
### Avoid deletions
This implementation of persistent vectors has many advantages, but it does
not support efficient deletion, with the exception of the last element that
can be popped very efficiently (`Aja.Vector.pop_last/1`, `Aja.Vector.delete_last/1`).
Deleting close to the end of the vector using `Aja.Vector.delete_at/2` or
`Aja.Vector.pop_at/3` is still fairly fast, but deleting near the beginning needs
to reconstruct most of the vector.
If you need to be able to delete arbitrary indexes, chances are you should consider
an alternative data structure.
Another possibility could be to use sparse arrays, defining `nil` as a deleted value
(but then the indexing and size won't reflect this).
**DON'T**
Aja.Vector.pop_at(vector, 3)
Aja.Vector.delete_at(vector, 3)
pop_in(vector[3])
**DO**
Aja.Vector.pop_last(vector)
Aja.Vector.delete_last(vector)
Aja.Vector.delete_at(vector, -3) # close to the end
Aja.Vector.replace_at(vector, 3, nil)
### Successive appends
If you just need to append all elements of an enumerable, it is more efficient to use
`Aja.Vector.concat/2` or its alias `Aja.+++/2` than successive calls to `Aja.Vector.append/2`:
**DON'T**
Enum.reduce(enumerable, vector, fn val, acc -> Aja.Vector.append(acc, val) end)
**DO**
Aja.Vector.concat(vector, enumerable)
#{if Version.compare(System.version(), "1.11.0") != :lt do
"vector +++ enumerable"
end}
### Prefer `Aja.Enum` and `Aja.Vector` to `Enum` for vectors
The `Aja.Enum` module reimplements (nearly) all functions from the `Enum` module to offer
optimal performance when operating on vectors, and should be used over `Enum` functions whenever possible
(even if `Aja.Vector` implements the `Enumerable` and `Collectable` protocols for convienience):
**DON'T**
Enum.sum(vector)
Enum.to_list(vector)
Enum.reduce(vector, [], fun)
Enum.into(enumerable, %Aja.Vector.new())
Enum.into(enumerable, vector)
**DO**
Aja.Enum.sum(vector)
Aja.Enum.to_list(vector) # or Aja.Vector.to_list(vector)
Aja.Enum.reduce(vector, [], fun) # or Aja.Vector.foldl(vector, [], fun)
Aja.Vector.new(enumerable)
Aja.Enum.into(enumerable, vector)
# or Aja.Vector.concat(vector, enumerable)
# or vector +++ enumerable
Although it depends on the function, you can expect a ~10x speed difference.
`for` comprehensions are actually using `Enumerable` as well, so
the same advice holds:
**DON'T**
for value <- vector do
do_stuff()
end
If using it in EEx templates, you might want to cast it to a list:
for value <- Aja.Vector.to_list(vector) do
do_stuff()
end
### Exceptions: `Enum` optimized functions
`Enum.member?/2` is implemented in an efficient way, so `in/2` is optimal:
**DO**
33 in vector
### Slicing optimization
Slicing any subset on the left on the vector using methods from `Aja.Vector` is
extremely efficient as the vector internals can be reused:
**DO**
Aja.Vector.take(vector, 10) # take a positive amount
Aja.Vector.drop(vector, -20) # drop a negative amount
Aja.Vector.slice(vector, 0, 10) # slicing from 0
Aja.Vector.slice(vector, 0..-5) # slicing from 0
### `Aja.Vector` and `Aja.Enum`
- `Aja.Enum` mirrors `Enum` and should return identical results, therefore many functions would return lists
- `Aja.Vector` mirrors `Enum` functions that are returning lists, but returns vectors instead
iex> vector = Aja.Vector.new(1..5)
iex> Aja.Enum.reverse(vector)
[5, 4, 3, 2, 1]
iex> Aja.Vector.reverse(vector)
vec([5, 4, 3, 2, 1])
iex> Aja.Enum.map(vector, & (&1 * 7))
[7, 14, 21, 28, 35]
iex> Aja.Vector.map(vector, & (&1 * 7))
vec([7, 14, 21, 28, 35])
### Additional notes
* If you need to work with vectors containing mostly the same value,
use `Aja.Vector.duplicate/2` (more details in the [Memory usage section](#module-memory-usage)).
* If you work with functions returning vectors of known size, you can use
the `Aja.vec/1` macro to defer the generation of the AST for the internal
structure to compile time instead of runtime.
Aja.Vector.new([%{foo: a}, %{foo: b}]) # structure created at runtime
vec([%{foo: a}, %{foo: b}]) # structure AST defined at compile time
"""
alias Aja.Vector.{EmptyError, IndexError, Raw}
require Raw
@behaviour Access
@type index :: integer
@type value :: term
@typep internals(value) :: %__MODULE__{__vector__: Raw.t(value)}
@typedoc """
The type of an `Aja.Vector` with elements of the type `value`.
It should be considered opaque even though it isn't enforced by dialyzer to enable pattern-matching.
"""
@type t(value) :: internals(value)
@type t :: t(value)
@enforce_keys [:__vector__]
defstruct [:__vector__]
@empty_raw Raw.empty()
defmacrop from_internal(internal) do
quote do
%__MODULE__{__vector__: unquote(internal)}
end
end
@doc """
Returns the number of elements in `vector`.
Runs in constant time.
## Examples
iex> Aja.Vector.new(10_000..20_000) |> Aja.Vector.size()
10001
iex> Aja.Vector.new() |> Aja.Vector.size()
0
"""
@compile {:inline, size: 1}
@spec size(t()) :: non_neg_integer
def size(%__MODULE__{__vector__: internal}) do
Raw.size(internal)
end
@doc """
Returns a new empty vector.
## Examples
iex> Aja.Vector.new()
vec([])
"""
@compile {:inline, new: 0}
@spec new :: t()
def new() do
from_internal(@empty_raw)
end
@doc """
Creates a vector from an `enumerable`.
Runs in linear time.
## Examples
iex> Aja.Vector.new(10..25)
vec([10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25])
"""
@spec new(Enumerable.t()) :: t()
def new(%__MODULE__{} = vector) do
vector
end
def new(enumerable) do
case Aja.EnumHelper.to_raw_vec_or_list(enumerable) do
list when is_list(list) -> from_list(list)
raw -> from_internal(raw)
end
end
@doc """
Creates a vector from an `enumerable` via the given `transform` function.
## Examples
iex> Aja.Vector.new(1..10, &(&1 * &1))
vec([1, 4, 9, 16, 25, 36, 49, 64, 81, 100])
"""
@spec new(Enumerable.t(), (v1 -> v2)) :: t(v2) when v1: value, v2: value
def new(enumerable, fun) when is_function(fun, 1) do
case Aja.EnumHelper.to_raw_vec_or_list(enumerable) do
list when is_list(list) -> Raw.from_mapped_list(list, fun) |> from_internal()
raw -> Raw.map(raw, fun) |> from_internal()
end
end
@doc """
Duplicates the given element `n` times in a vector.
`n` is an integer greater than or equal to `0`.
If `n` is `0`, an empty list is returned.
Runs in logarithmic time regarding `n`. It is very fast and memory efficient
(see [Memory usage](#module-memory-usage)).
## Examples
iex> Aja.Vector.duplicate(nil, 10)
vec([nil, nil, nil, nil, nil, nil, nil, nil, nil, nil])
iex> Aja.Vector.duplicate(:foo, 0)
vec([])
"""
@spec duplicate(val, non_neg_integer) :: t(val) when val: value
def duplicate(value, n) when is_integer(n) and n >= 0 do
Raw.duplicate(value, n) |> from_internal()
end
@doc """
Populates a vector of size `n` by calling `generator_fun` repeatedly.
## Examples
# Although not necessary, let's seed the random algorithm
iex> :rand.seed(:exrop, {1, 2, 3})
iex> Aja.Vector.repeat(&:rand.uniform/0, 3)
vec([0.7498295129076106, 0.06161655489244533, 0.7924073127680873])
"""
def repeat(generator_fun, n)
when is_function(generator_fun, 0) and is_integer(n) and n >= 0 do
Aja.List.repeat(generator_fun, n) |> from_list()
end
@doc """
Appends a `value` at the end of a `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new() |> Aja.Vector.append(:foo)
vec([:foo])
iex> Aja.Vector.new(1..5) |> Aja.Vector.append(:foo)
vec([1, 2, 3, 4, 5, :foo])
"""
@spec append(t(val), val) :: t(val) when val: value
def append(%__MODULE__{__vector__: internal}, value) do
Raw.append(internal, value) |> from_internal()
end
@doc """
Appends all values from an `enumerable` at the end of a `vector`.
Runs in effective linear time in respect with the length of `enumerable`,
disregarding the size of the `vector`.
## Examples
iex> Aja.Vector.new(1..5) |> Aja.Vector.concat(10..15)
vec([1, 2, 3, 4, 5, 10, 11, 12, 13, 14, 15])
iex> Aja.Vector.new() |> Aja.Vector.concat(10..15)
vec([10, 11, 12, 13, 14, 15])
"""
@spec concat(t(val), Enumerable.t()) :: t(val) when val: value
def concat(%__MODULE__{__vector__: internal}, enumerable) do
case Aja.EnumHelper.to_raw_vec_or_list(enumerable) do
list when is_list(list) -> Raw.concat_list(internal, list)
vector when is_tuple(vector) -> Raw.concat_vector(internal, vector)
end
|> from_internal()
end
@doc """
(Inefficient) Prepends `value` at the beginning of the `vector`.
Runs in linear time because the whole vector needs to be reconstructuded,
and should be avoided.
## Examples
iex> Aja.Vector.new() |> Aja.Vector.prepend(:foo)
vec([:foo])
iex> Aja.Vector.new(1..5) |> Aja.Vector.prepend(:foo)
vec([:foo, 1, 2, 3, 4, 5])
"""
@spec prepend(t(val), val) :: t(val) when val: value
def prepend(%__MODULE__{__vector__: internal}, value) do
Raw.prepend(internal, value) |> from_internal()
end
@doc """
Returns the first element in the `vector` or `default` if `vector` is empty.
Runs in actual constant time.
## Examples
iex> Aja.Vector.new(1..10_000) |> Aja.Vector.first()
1
iex> Aja.Vector.new() |> Aja.Vector.first()
nil
"""
@spec first(t(val), default) :: val | default when val: value, default: term
def first(vector, default \\ nil)
def first(%__MODULE__{__vector__: internal}, default) do
case internal do
Raw.first_pattern(first) -> first
_ -> default
end
end
@doc """
Returns the last element in the `vector` or `default` if `vector` is empty.
Runs in constant time (actual, not effective).
## Examples
iex> Aja.Vector.new(1..10_000) |> Aja.Vector.last()
10_000
iex> Aja.Vector.new() |> Aja.Vector.last()
nil
"""
@spec last(t(val), default) :: val | default when val: value, default: term
def last(vector, default \\ nil)
def last(%__MODULE__{__vector__: internal}, default) do
case internal do
Raw.last_pattern(last) -> last
_ -> default
end
end
@doc """
Finds the element at the given `index` (zero-based), and returns it in a ok-entry.
If the `index` does not exist, returns `:error`.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.fetch(555)
{:ok, 556}
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.fetch(1_000)
:error
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.fetch(-1)
{:ok, 1000}
"""
@impl Access
@spec fetch(t(val), index) :: {:ok, val} | :error when val: value
def fetch(vector, index)
def fetch(%__MODULE__{__vector__: internal}, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
:error
actual_index ->
found = Raw.fetch_positive!(internal, actual_index)
{:ok, found}
end
end
defdelegate fetch!(vector, index), to: __MODULE__, as: :at!
@doc """
Finds the element at the given `index` (zero-based).
Returns `default` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.at(555)
556
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.at(1_000)
nil
"""
@spec at(t(val), index) :: val | nil when val: value
def at(%__MODULE__{__vector__: internal}, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil -> nil
actual_index -> Raw.fetch_positive!(internal, actual_index)
end
end
@spec at(t(val), index, default) :: val | default when val: value, default: term
def at(%__MODULE__{__vector__: internal}, index, default) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil -> default
actual_index -> Raw.fetch_positive!(internal, actual_index)
end
end
@doc """
Finds the element at the given `index` (zero-based).
Raises an `Aja.Vector.IndexError` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.at!(555)
556
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.at!(-10)
991
iex> Aja.Vector.new(1..1_000) |> Aja.Vector.at!(1_000)
** (Aja.Vector.IndexError) out of bound index: 1000 not in -1000..999
"""
@spec at!(t(val), index) :: val when val: value
def at!(%__MODULE__{__vector__: internal}, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil -> raise IndexError, index: index, size: size
actual_index -> Raw.fetch_positive!(internal, actual_index)
end
end
@doc """
Returns a copy of `vector` with a replaced `value` at the specified `index`.
Returns the `vector` untouched if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at(5, :foo)
vec([1, 2, 3, 4, 5, :foo, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at(8, :foo)
vec([1, 2, 3, 4, 5, 6, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at(-2, :foo)
vec([1, 2, 3, 4, 5, 6, :foo, 8])
"""
@spec replace_at(t(val), index, val) :: t(val) when val: value
def replace_at(%__MODULE__{__vector__: internal} = vector, index, value)
when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
vector
actual_index ->
Raw.replace_positive!(internal, actual_index, value) |> from_internal()
end
end
@doc """
Returns a copy of `vector` with a replaced `value` at the specified `index`.
Raises an `Aja.Vector.IndexError` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at!(5, :foo)
vec([1, 2, 3, 4, 5, :foo, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at!(-2, :foo)
vec([1, 2, 3, 4, 5, 6, :foo, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.replace_at!(8, :foo)
** (Aja.Vector.IndexError) out of bound index: 8 not in -8..7
"""
@spec replace_at!(t(val), index, val) :: t(val) when val: value
def replace_at!(%__MODULE__{__vector__: internal}, index, value)
when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
raise IndexError, index: index, size: size
actual_index ->
Raw.replace_positive!(internal, actual_index, value) |> from_internal()
end
end
@doc """
Returns a copy of `vector` with an updated value at the specified `index`.
Returns the `vector` untouched if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at(2, &(&1 * 1000))
vec([1, 2, 3000, 4, 5, 6, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at(8, &(&1 * 1000))
vec([1, 2, 3, 4, 5, 6, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at(-1, &(&1 * 1000))
vec([1, 2, 3, 4, 5, 6, 7, 8000])
"""
@spec update_at(t(val), index, (val -> val)) :: t(val) when val: value
def update_at(%__MODULE__{__vector__: internal} = vector, index, fun)
when is_integer(index) and is_function(fun) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
vector
actual_index ->
Raw.update_positive!(internal, actual_index, fun) |> from_internal()
end
end
@doc """
Returns a copy of `vector` with an updated value at the specified `index`.
Raises an `Aja.Vector.IndexError` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in effective constant time.
## Examples
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at!(2, &(&1 * 1000))
vec([1, 2, 3000, 4, 5, 6, 7, 8])
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at!(-1, &(&1 * 1000))
vec([1, 2, 3, 4, 5, 6, 7, 8000])
iex> Aja.Vector.new(1..8) |> Aja.Vector.update_at!(-9, &(&1 * 1000))
** (Aja.Vector.IndexError) out of bound index: -9 not in -8..7
"""
@spec update_at!(t(val), index, (val -> val)) :: t(val) when val: value
def update_at!(%__MODULE__{__vector__: internal}, index, fun)
when is_integer(index) and is_function(fun) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
raise IndexError, index: index, size: size
actual_index ->
Raw.update_positive!(internal, actual_index, fun) |> from_internal()
end
end
@doc """
Removes the last value from the `vector` and returns both the value and the updated vector.
Leaves the `vector` untouched if empty.
Runs in effective constant time.
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> {8, updated} = Aja.Vector.pop_last(vector); updated
vec([1, 2, 3, 4, 5, 6, 7])
iex> {nil, updated} = Aja.Vector.pop_last(Aja.Vector.new()); updated
vec([])
"""
@spec pop_last(t(val), default) :: {val | default, t(val)} when val: value, default: term
def pop_last(vector, default \\ nil)
def pop_last(%__MODULE__{__vector__: internal} = vector, default) do
case Raw.pop_last(internal) do
{value, new_internal} -> {value, from_internal(new_internal)}
:error -> {default, vector}
end
end
@doc """
Removes the last value from the `vector` and returns both the value and the updated vector.
Raises an `Aja.Vector.EmptyError` if empty.
Runs in effective constant time.
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> {8, updated} = Aja.Vector.pop_last!(vector); updated
vec([1, 2, 3, 4, 5, 6, 7])
iex> {nil, updated} = Aja.Vector.pop_last!(Aja.Vector.new()); updated
** (Aja.Vector.EmptyError) empty vector error
"""
@spec pop_last!(t(val)) :: {val, t(val)} when val: value
def pop_last!(vector)
def pop_last!(%__MODULE__{__vector__: internal}) do
case Raw.pop_last(internal) do
{value, new_internal} -> {value, from_internal(new_internal)}
:error -> raise EmptyError
end
end
@doc """
Removes the last value from the `vector` and returns the updated vector.
Leaves the `vector` untouched if empty.
Runs in effective constant time.
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> Aja.Vector.delete_last(vector)
vec([1, 2, 3, 4, 5, 6, 7])
iex> Aja.Vector.delete_last(Aja.Vector.new())
vec([])
"""
@spec delete_last(t(val)) :: t(val) when val: value
def delete_last(vector)
def delete_last(%__MODULE__{__vector__: internal} = vector) do
case Raw.pop_last(internal) do
{_value, new_internal} -> from_internal(new_internal)
:error -> vector
end
end
@doc """
Removes the last value from the `vector` and returns the updated vector.
Raises an `Aja.Vector.EmptyError` if empty.
Runs in effective constant time.
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> Aja.Vector.delete_last!(vector)
vec([1, 2, 3, 4, 5, 6, 7])
iex> Aja.Vector.delete_last!(Aja.Vector.new())
** (Aja.Vector.EmptyError) empty vector error
"""
@spec delete_last!(t(val)) :: t(val) when val: value
def delete_last!(vector)
def delete_last!(%__MODULE__{__vector__: internal}) do
case Raw.pop_last(internal) do
{_value, new_internal} -> from_internal(new_internal)
:error -> raise EmptyError
end
end
@doc """
(Inefficient) Returns and removes the value at the specified `index` in the `vector`.
Returns the `vector` untouched if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in linear time. Its usage is discouraged, see the
[Efficiency guide](#module-efficiency-guide).
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> {5, updated} = Aja.Vector.pop_at(vector, 4); updated
vec([1, 2, 3, 4, 6, 7, 8])
iex> {nil, updated} = Aja.Vector.pop_at(vector, -9); updated
vec([1, 2, 3, 4, 5, 6, 7, 8])
"""
@spec pop_at(t(val), index, default) :: {val | default, t(val)} when val: value, default: term
def pop_at(vector, index, default \\ nil)
def pop_at(%__MODULE__{__vector__: internal} = vector, index, default) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
{default, vector}
actual_index ->
{value, new_internal} = Raw.pop_positive!(internal, actual_index, size)
{value, from_internal(new_internal)}
end
end
@doc """
(Inefficient) Returns and removes the value at the specified `index` in the `vector`.
Raises an `Aja.Vector.IndexError` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in linear time. Its usage is discouraged, see the
[Efficiency guide](#module-efficiency-guide).
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> {5, updated} = Aja.Vector.pop_at!(vector, 4); updated
vec([1, 2, 3, 4, 6, 7, 8])
iex> Aja.Vector.pop_at!(vector, -9)
** (Aja.Vector.IndexError) out of bound index: -9 not in -8..7
"""
@spec pop_at!(t(val), index) :: {val, t(val)} when val: value
def pop_at!(vector, index)
def pop_at!(%__MODULE__{__vector__: internal}, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
raise IndexError, index: index, size: size
actual_index ->
{value, new_internal} = Raw.pop_positive!(internal, actual_index, size)
{value, from_internal(new_internal)}
end
end
@doc false
@impl Access
@spec pop(t(val), index) :: {val | nil, t(val)} when val: value
defdelegate pop(vector, key), to: __MODULE__, as: :pop_at
@doc """
(Inefficient) Returns a copy of `vector` without the value at the specified `index`.
Returns the `vector` untouched if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in linear time. Its usage is discouraged, see the
[Efficiency guide](#module-efficiency-guide).
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> Aja.Vector.delete_at(vector, 4)
vec([1, 2, 3, 4, 6, 7, 8])
iex> Aja.Vector.delete_at(vector, -9)
vec([1, 2, 3, 4, 5, 6, 7, 8])
"""
@spec delete_at(t(val), index) :: t(val) when val: value
def delete_at(%__MODULE__{__vector__: internal} = vector, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
vector
actual_index ->
Raw.delete_positive!(internal, actual_index, size) |> from_internal()
end
end
@doc """
(Inefficient) Returns a copy of `vector` without the value at the specified `index`.
Raises an `Aja.Vector.IndexError` if `index` is out of bounds.
Supports negative indexing from the end of the `vector`.
Runs in linear time. Its usage is discouraged, see the
[Efficiency guide](#module-efficiency-guide).
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> Aja.Vector.delete_at!(vector, 4)
vec([1, 2, 3, 4, 6, 7, 8])
iex> Aja.Vector.delete_at!(vector, -9)
** (Aja.Vector.IndexError) out of bound index: -9 not in -8..7
"""
@spec delete_at!(t(val), index) :: t(val) when val: value
def delete_at!(vector, index)
def delete_at!(%__MODULE__{__vector__: internal}, index) when is_integer(index) do
size = Raw.size(internal)
case Raw.actual_index(index, size) do
nil ->
raise IndexError, index: index, size: size
actual_index ->
Raw.delete_positive!(internal, actual_index, size) |> from_internal()
end
end
@doc """
Gets the value from key and updates it, all in one pass.
See `Access.get_and_update/3` for more details.
## Examples
iex> vector = Aja.Vector.new(1..8)
iex> {6, updated} = Aja.Vector.get_and_update(vector, 5, fn current_value ->
...> {current_value, current_value && current_value * 100}
...> end); updated
vec([1, 2, 3, 4, 5, 600, 7, 8])
iex> {nil, updated} = Aja.Vector.get_and_update(vector, 8, fn current_value ->
...> {current_value, current_value && current_value * 100}
...> end); updated
vec([1, 2, 3, 4, 5, 6, 7, 8])
iex> {4, updated} = Aja.Vector.get_and_update(vector, 3, fn _ -> :pop end); updated
vec([1, 2, 3, 5, 6, 7, 8])
iex> {nil, updated} = Aja.Vector.get_and_update(vector, 8, fn _ -> :pop end); updated
vec([1, 2, 3, 4, 5, 6, 7, 8])
"""
@impl Access
@spec get_and_update(t(v), index, (v -> {returned, v} | :pop)) :: {returned, t(v)}
when v: value, returned: term
def get_and_update(%__MODULE__{__vector__: internal}, index, fun)
when is_integer(index) and is_function(fun, 1) do
{returned, new_internal} = Raw.get_and_update(internal, index, fun)
{returned, from_internal(new_internal)}
end
@doc """
Converts the `vector` to a list.
Runs in linear time.
## Examples
iex> Aja.Vector.new(10..25) |> Aja.Vector.to_list()
[10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]
iex> Aja.Vector.new() |> Aja.Vector.to_list()
[]
"""
@spec to_list(t(val)) :: [val] when val: value
def to_list(%__MODULE__{__vector__: internal}) do
Raw.to_list(internal)
end
@doc """
Returns a new vector where each element is the result of invoking `fun`
on each corresponding element of `vector`.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.map(&(&1 * &1))
vec([1, 4, 9, 16, 25, 36, 49, 64, 81, 100])
"""
@spec map(t(v1), (v1 -> v2)) :: t(v2) when v1: value, v2: value
def map(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
Raw.map(internal, fun) |> from_internal()
end
@doc """
Filters the `vector`, i.e. return a new vector containing only elements
for which `fun` returns a truthy (neither `false` nor `nil`) value.
Runs in linear time.
## Examples
iex> vector = Aja.Vector.new(1..100)
iex> Aja.Vector.filter(vector, fn i -> rem(i, 13) == 0 end)
vec([13, 26, 39, 52, 65, 78, 91])
"""
@spec filter(t(val), (val -> as_boolean(term))) :: t(val) when val: value
def filter(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
Raw.filter_to_list(internal, fun) |> from_list()
end
@doc """
Filters the `vector`, i.e. return a new vector containing only elements
for which `fun` returns a falsy (either `false` or `nil`) value.
Runs in linear time.
## Examples
iex> vector = Aja.Vector.new(1..12)
iex> Aja.Vector.reject(vector, fn i -> rem(i, 3) == 0 end)
vec([1, 2, 4, 5, 7, 8, 10, 11])
"""
@spec reject(t(val), (val -> as_boolean(term))) :: t(val) when val: value
def reject(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
Raw.reject_to_list(internal, fun) |> from_list()
end
@doc """
Splits the `vector` in two vectors according to the given function `fun`.
Returns a tuple with the first vector containing all the elements in `vector`
for which applying `fun` returned a truthy value, and a second vector with all
the elements for which applying `fun` returned a falsy value (`false` or `nil`).
Returns the same result as `filter/2` and `reject/2` at once, but only walks the
`vector` once and calls `fun` exactly once per element.
Runs in linear time.
## Examples
iex> vector = Aja.Vector.new(1..12)
iex> {filtered, rejected} = Aja.Vector.split_with(vector, fn i -> rem(i, 3) == 0 end)
iex> filtered
vec([3, 6, 9, 12])
iex> rejected
vec([1, 2, 4, 5, 7, 8, 10, 11])
"""
@spec split_with(t(val), (val -> as_boolean(term))) :: {t(val), t(val)} when val: value
def split_with(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
# note: unlike filter/2, optimization does not bring much benefit
{filtered, rejected} = internal |> Raw.to_list() |> Enum.split_with(fun)
{from_list(filtered), from_list(rejected)}
end
@doc """
Sorts the `vector` in the same way as `Enum.sort/1`.
## Examples
iex> Aja.Vector.new(9..1) |> Aja.Vector.sort()
vec([1, 2, 3, 4, 5, 6, 7, 8, 9])
"""
@spec sort(t(val)) :: t(val) when val: value
def sort(%__MODULE__{__vector__: internal}) do
internal
|> Raw.to_list()
|> Enum.sort()
|> from_list()
end
@doc """
Sorts the `vector` in the same way as `Enum.sort/2`.
See `Enum.sort/2` documentation for detailled usage.
## Examples
iex> Aja.Vector.new(1..9) |> Aja.Vector.sort(:desc)
vec([9, 8, 7, 6, 5, 4, 3, 2, 1])
"""
@spec sort(
t(val),
(val, val -> boolean)
| :asc
| :desc
| module
| {:asc | :desc, module}
) :: t(val)
when val: value
def sort(%__MODULE__{__vector__: internal}, fun) do
internal
|> Raw.to_list()
|> Enum.sort(fun)
|> from_list()
end
@doc """
Sorts the `vector` in the same way as `Enum.sort_by/3`.
See `Enum.sort_by/3` documentation for detailled usage.
## Examples
iex> vector = Aja.Vector.new(["some", "kind", "of", "monster"])
iex> Aja.Vector.sort_by(vector, &byte_size/1)
vec(["of", "some", "kind", "monster"])
iex> Aja.Vector.sort_by(vector, &{byte_size(&1), String.first(&1)})
vec(["of", "kind", "some", "monster"])
"""
@spec sort_by(
t(val),
(val -> mapped_val),
(val, val -> boolean)
| :asc
| :desc
| module
| {:asc | :desc, module}
) :: t(val)
when val: value, mapped_val: value
def sort_by(%__MODULE__{__vector__: internal}, mapper, sorter \\ &<=/2) do
internal
|> Raw.to_list()
|> Enum.sort_by(mapper, sorter)
|> from_list()
end
@doc """
Returns a copy of the vector without any duplicated element.
The first occurrence of each element is kept.
## Examples
iex> Aja.Vector.new([1, 1, 2, 1, 2, 3, 2]) |> Aja.Vector.uniq()
vec([1, 2, 3])
"""
@spec uniq(t(val)) :: t(val) when val: value
def uniq(%__MODULE__{__vector__: internal}) do
internal
|> Raw.uniq_list()
|> from_list()
end
@doc """
Returns a copy of the vector without elements for which the function `fun` returned duplicate elements.
The first occurrence of each element is kept.
## Examples
iex> vector = Aja.Vector.new([x: 1, y: 2, z: 1])
vec([x: 1, y: 2, z: 1])
iex> Aja.Vector.uniq_by(vector, fn {_x, y} -> y end)
vec([x: 1, y: 2])
"""
@spec uniq_by(t(val), (val -> term)) :: t(val) when val: value
def uniq_by(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
internal
|> Raw.uniq_by_list(fun)
|> from_list()
end
@doc """
Returns a copy of the `vector` where all consecutive duplicated elements are collapsed to a single element.
Elements are compared using `===/2`.
If you want to remove all duplicated elements, regardless of order, see `uniq/1`.
## Examples
iex> Aja.Vector.new([1, 2, 3, 3, 2, 1]) |> Aja.Vector.dedup()
vec([1, 2, 3, 2, 1])
iex> Aja.Vector.new([1, 1, 2, 2.0, :three, :three]) |> Aja.Vector.dedup()
vec([1, 2, 2.0, :three])
"""
@spec dedup(t(val)) :: t(val) when val: value
def dedup(%__MODULE__{__vector__: internal}) do
internal
|> Raw.dedup_list()
|> from_list()
end
@doc """
Returns a copy of the `vector` where all consecutive duplicated elements are collapsed to a single element.
The function `fun` maps every element to a term which is used to determine if two elements are duplicates.
## Examples
iex> vector = Aja.Vector.new([{1, :a}, {2, :b}, {2, :c}, {1, :a}])
iex> Aja.Vector.dedup_by(vector, fn {x, _} -> x end)
vec([{1, :a}, {2, :b}, {1, :a}])
iex> vector = Aja.Vector.new([5, 1, 2, 3, 2, 1])
iex> Aja.Vector.dedup_by(vector, fn x -> x > 2 end)
vec([5, 1, 3, 2])
"""
@spec dedup_by(t(val), (val -> term)) :: t(val) when val: value
def dedup_by(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 1) do
internal
|> Raw.to_list()
|> Enum.dedup_by(fun)
|> from_list()
end
@doc """
Intersperses `separator` between each element of the `vector`.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..6) |> Aja.Vector.intersperse(nil)
vec([1, nil, 2, nil, 3, nil, 4, nil, 5, nil, 6])
"""
@spec intersperse(
t(val),
separator
) :: t(val | separator)
when val: value, separator: value
def intersperse(%__MODULE__{__vector__: internal}, separator) do
internal
|> Raw.intersperse_to_list(separator)
|> from_list()
end
@doc """
Maps and intersperses the `vector` in one pass.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..6) |> Aja.Vector.map_intersperse(nil, &(&1 * 10))
vec([10, nil, 20, nil, 30, nil, 40, nil, 50, nil, 60])
"""
@spec map_intersperse(
t(val),
separator,
(val -> mapped_val)
) :: t(mapped_val | separator)
when val: value, separator: value, mapped_val: value
def map_intersperse(%__MODULE__{__vector__: internal}, separator, mapper)
when is_function(mapper, 1) do
internal
|> Raw.map_intersperse_to_list(separator, mapper)
|> from_list()
end
@doc """
Maps the given `fun` over `vector` and flattens the result.
This function returns a new vector built by concatenating the results
of invoking `fun` on each element of `vector` together.
Runs in linear time.
## Examples
iex> Aja.Vector.new(0..4) |> Aja.Vector.flat_map(fn i -> List.duplicate(i, i) end)
vec([1, 2, 2, 3, 3, 3, 4, 4, 4, 4])
"""
@spec flat_map(t(val), (val -> t(mapped_val))) :: t(mapped_val)
when val: value, mapped_val: value
def flat_map(%__MODULE__{} = vector, fun) when is_function(fun, 1) do
vector
|> Aja.EnumHelper.flat_map(fun)
|> from_list()
end
@doc """
Folds (reduces) the given `vector` from the left with the function `fun`.
Requires an accumulator `acc`.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.foldl(0, &+/2)
55
iex> Aja.Vector.new(1..10) |> Aja.Vector.foldl([], & [&1 | &2])
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
"""
@spec foldl(t(val), acc, (val, acc -> acc)) :: acc when val: value, acc: term
def foldl(%__MODULE__{__vector__: internal}, acc, fun) when is_function(fun, 2) do
Raw.foldl(internal, acc, fun)
end
@doc """
Folds (reduces) the given `vector` from the right with the function `fun`.
Requires an accumulator `acc`.
Unlike linked lists, this is as efficient as `foldl/3`. This can typically save a call
to `Enum.reverse/1` on the result when building a list.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.foldr(0, &+/2)
55
iex> Aja.Vector.new(1..10) |> Aja.Vector.foldr([], & [&1 | &2])
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
"""
@spec foldr(t(val), acc, (val, acc -> acc)) :: acc when val: value, acc: term
def foldr(%__MODULE__{__vector__: internal}, acc, fun) when is_function(fun, 2) do
Raw.foldr(internal, acc, fun)
end
@doc """
Invokes the given `fun` to each element in the `vector` to reduce
it to a single element, while keeping an accumulator.
Returns a tuple where the first element is the mapped vector and
the second one is the final accumulator.
The function, `fun`, receives two arguments: the first one is the
element, and the second one is the accumulator. `fun` must return
a tuple with two elements in the form of `{result, accumulator}`.
## Examples
iex> vector = Aja.Vector.new([1, 2, 3])
iex> {new_vec, 6} = Aja.Vector.map_reduce(vector, 0, fn x, acc -> {x * 2, x + acc} end)
iex> new_vec
vec([2, 4, 6])
For example, if `with_index/2` was not implemented, you could implement it as follows:
iex> vector = Aja.Vector.new([1, 2, 3])
iex> Aja.Vector.map_reduce(vector, 0, fn x, i -> {{x, i}, i + 1} end) |> elem(0)
vec([{1, 0}, {2, 1}, {3, 2}])
"""
@spec map_reduce(t(val), acc, (val, acc -> {mapped_val, acc})) :: {t(mapped_val), acc}
when val: value, mapped_val: value, acc: any
def map_reduce(%__MODULE__{__vector__: internal}, acc, fun) when is_function(fun, 2) do
{new_raw, new_acc} = Raw.map_reduce(internal, acc, fun)
{from_internal(new_raw), new_acc}
end
@doc """
Applies the given function to each element in the `vector`, storing the result
in a vector and passing it as the accumulator for the next computation.
Uses the first element in the `vector` as the starting value.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.scan(&+/2)
vec([1, 3, 6, 10, 15, 21, 28, 36, 45, 55])
"""
@spec scan(t(val), (val, val -> val)) :: val when val: value
def scan(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 2) do
internal |> Raw.scan(fun) |> from_internal()
end
@doc """
Applies the given function to each element in the `vector`, storing the result
in a vector and passing it as the accumulator for the next computation.
Uses the given `acc` as the starting value.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.scan(100, &+/2)
vec([101, 103, 106, 110, 115, 121, 128, 136, 145, 155])
"""
@spec scan(t(val), acc, (val, acc -> acc)) :: acc when val: value, acc: term
def scan(%__MODULE__{__vector__: internal}, acc, fun) when is_function(fun, 2) do
internal |> Raw.scan(acc, fun) |> from_internal()
end
@doc """
Returns the `vector` in reverse order.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..12) |> Aja.Vector.reverse()
vec([12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1])
"""
@spec reverse(t(val)) :: t(val) when val: value
def reverse(%__MODULE__{__vector__: internal}) do
internal
|> Raw.reverse_to_list([])
|> from_list()
end
@doc """
Returns the `vector` in reverse order, and concatenates the `tail` (enumerable).
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..5) |> Aja.Vector.reverse(100..105)
vec([5, 4, 3, 2, 1, 100, 101, 102, 103, 104, 105])
"""
@spec reverse(t(val), Enumerable.t()) :: t(val) when val: value
def reverse(%__MODULE__{__vector__: internal}, tail) do
internal
|> Raw.reverse_to_list(Aja.EnumHelper.to_list(tail))
|> from_list()
end
@doc """
Returns a subset of the given `vector` by `index_range`.
Works the same as `Enum.slice/2`, see its documentation for more details.
Runs in linear time regarding the size of the returned subset.
## Examples
iex> Aja.Vector.new(0..100) |> Aja.Vector.slice(80..90)
vec([80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90])
iex> Aja.Vector.new(0..100) |> Aja.Vector.slice(-40..-30//1)
vec([61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71])
iex> Aja.Vector.new([:only_one]) |> Aja.Vector.slice(0..1000)
vec([:only_one])
"""
@spec slice(t(val), Range.t()) :: t(val) when val: value
def slice(%__MODULE__{} = vector, first..last = index_range) do
case first do
0 ->
amount = last + 1
if last < 0 do
drop(vector, amount)
else
take(vector, amount)
end
_ ->
vector
|> Enum.slice(index_range)
|> from_list()
end
end
@doc """
Returns a subset of the given `vector`, from `start_index` (zero-based)
with `amount number` of elements if available.
Works the same as `Enum.slice/3`, see its documentation for more details.
Runs in linear time regarding the size of the returned subset.
## Examples
iex> Aja.Vector.new(0..100) |> Aja.Vector.slice(80, 10)
vec([80, 81, 82, 83, 84, 85, 86, 87, 88, 89])
iex> Aja.Vector.new(0..100) |> Aja.Vector.slice(-40, 10)
vec([61, 62, 63, 64, 65, 66, 67, 68, 69, 70])
iex> Aja.Vector.new([:only_one]) |> Aja.Vector.slice(0, 1000)
vec([:only_one])
"""
@spec slice(t(val), index, non_neg_integer) :: t(val) when val: value
def slice(%__MODULE__{__vector__: internal} = vector, start_index, amount)
when is_integer(start_index) and is_integer(amount) and amount >= 0 do
if start_index == 0 or start_index == -Raw.size(internal) do
Raw.take(internal, amount) |> from_internal()
else
vector
|> Enum.slice(start_index, amount)
|> from_list()
end
end
@doc """
Takes an `amount` of elements from the beginning or the end of the `vector`.
If a positive `amount` is given, it takes the amount elements from the beginning of the `vector`.
If a negative `amount` is given, the amount of elements will be taken from the end.
If amount is 0, it returns the empty vector.
Time complexity is:
- effective constant time when `amount` is positive, as the vector structure can be shared
- linear when `amount` is negative, as the vector needs to be reconstructed.
## Examples
iex> Aja.Vector.new(0..100) |> Aja.Vector.take(10)
vec([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
iex> Aja.Vector.new([:only_one]) |> Aja.Vector.take(1000)
vec([:only_one])
iex> Aja.Vector.new(0..10) |> Aja.Vector.take(-5)
vec([6, 7, 8, 9, 10])
"""
@spec take(t(val), integer) :: t(val) when val: value
def take(%__MODULE__{__vector__: internal}, amount) when is_integer(amount) do
do_take(internal, amount) |> from_internal()
end
defp do_take(internal, amount) when amount < 0 do
size = Raw.size(internal)
case size + amount do
start when start > 0 ->
internal
|> Raw.slice(start, size - 1)
|> Raw.from_list()
_ ->
internal
end
end
defp do_take(internal, amount) do
Raw.take(internal, amount)
end
@doc """
Drops the amount of elements from the `vector`.
If a negative `amount` is given, the amount of last values will be dropped.
Time complexity is:
- linear when `amount` is positive, as the vector needs to be reconstructed.
- effective constant time when `amount` is negative, as the vector structure can be shared
## Examples
iex> Aja.Vector.new(0..15) |> Aja.Vector.drop(10)
vec([10, 11, 12, 13, 14, 15])
iex> Aja.Vector.new(0..5) |> Aja.Vector.drop(0)
vec([0, 1, 2, 3, 4, 5])
iex> Aja.Vector.new(0..10) |> Aja.Vector.drop(-5)
vec([0, 1, 2, 3, 4, 5])
"""
@spec drop(t(val), integer) :: t(val) when val: value
def drop(%__MODULE__{__vector__: internal}, amount) when is_integer(amount) do
do_drop(internal, amount) |> from_internal()
end
defp do_drop(internal, _amount = 0) do
internal
end
defp do_drop(internal, amount) when amount < 0 do
size = Raw.size(internal)
case size + amount do
keep when keep > 0 -> Raw.take(internal, size + amount)
_ -> @empty_raw
end
end
defp do_drop(internal, amount) do
size = Raw.size(internal)
if amount >= size do
@empty_raw
else
internal
|> Raw.slice(amount, size - 1)
|> Raw.from_list()
end
end
@doc """
Splits the `vector` into two vectors, leaving `amount` elements in the first one.
If `amount` is a negative number, it starts counting from the back to the beginning of the `vector`.
Runs in linear time.
## Examples
iex> vector = Aja.Vector.new([1, 2, 3])
iex> Aja.Vector.split(vector, 2) |> inspect()
"{vec([1, 2]), vec([3])}"
iex> Aja.Vector.split(vector, 10) |> inspect()
"{vec([1, 2, 3]), vec([])}"
iex> Aja.Vector.split(vector, 0) |> inspect()
"{vec([]), vec([1, 2, 3])}"
iex> Aja.Vector.split(vector, -1) |> inspect()
"{vec([1, 2]), vec([3])}"
iex> Aja.Vector.split(vector, -5) |> inspect()
"{vec([]), vec([1, 2, 3])}"
"""
@spec split(t(val), integer) :: {t(val), t(val)} when val: value
def split(%__MODULE__{__vector__: internal} = vector, amount) when is_integer(amount) do
size = Raw.size(internal)
case Raw.actual_index(amount, size) do
nil ->
case amount do
positive when positive > 0 -> {vector, new()}
_ -> {new(), vector}
end
actual_amount ->
taken = Raw.take(internal, actual_amount)
dropped = do_drop(internal, actual_amount)
{from_internal(taken), from_internal(dropped)}
end
end
@doc """
Takes the elements from the beginning of the `vector` while `fun` returns a truthy value.
Runs in linear time regarding the size of the returned subset.
## Examples
iex> Aja.Vector.new(1..100) |> Aja.Vector.take_while(fn x -> x < 7 end)
vec([1, 2, 3, 4, 5, 6])
iex> Aja.Vector.new([1, true, %{}, nil, "abc"]) |> Aja.Vector.take_while(fn x -> x end)
vec([1, true, %{}])
"""
@spec take_while(t(val), (val -> as_boolean(term()))) :: t(val) when val: value
def take_while(%__MODULE__{__vector__: internal} = vector, fun) when is_function(fun, 1) do
case Raw.find_falsy_index(internal, fun) do
nil ->
vector
index ->
Raw.take(internal, index) |> from_internal()
end
end
@doc """
Drops elements at the beginning of the `vector` while `fun` returns a truthy value.
Runs in linear time.
## Examples
iex> Aja.Vector.new(1..10) |> Aja.Vector.drop_while(fn x -> x < 7 end)
vec([7, 8, 9, 10])
iex> Aja.Vector.new([1, true, %{}, nil, "abc"]) |> Aja.Vector.drop_while(fn x -> x end)
vec([nil, "abc"])
"""
@spec drop_while(t(val), (val -> as_boolean(term()))) :: t(val) when val: value
def drop_while(%__MODULE__{__vector__: internal} = vector, fun) when is_function(fun, 1) do
case Raw.find_falsy_index(internal, fun) do
nil ->
new()
0 ->
vector
index ->
size = Raw.size(internal)
internal
|> Raw.slice(index, size - 1)
|> from_list()
end
end
@doc """
Splits `vector` in two at the position of the element for which `fun` returns a falsy value
(`false` or `nil`) for the first time.
It returns a two-element tuple with two vectors of elements.
The element that triggered the split is part of the second vector.
Is basically performing `take_while/2` and `drop_while/2` at once.
Runs in linear time.
## Examples
iex> {taken, dropped} = Aja.Vector.new(1..10) |> Aja.Vector.split_while(fn x -> x < 7 end)
iex> taken
vec([1, 2, 3, 4, 5, 6])
iex> dropped
vec([7, 8, 9, 10])
"""
@spec split_while(t(val), (val -> as_boolean(term()))) :: {t(val), t(val)} when val: value
def split_while(%__MODULE__{__vector__: internal} = vector, fun) when is_function(fun, 1) do
case Raw.find_falsy_index(internal, fun) do
nil ->
{vector, new()}
0 ->
{new(), vector}
index ->
size = Raw.size(internal)
taken = Raw.take(internal, index) |> from_internal()
dropped =
internal
|> Raw.slice(index, size - 1)
|> from_list()
{taken, dropped}
end
end
@doc ~S"""
Returns the `vector` with each element wrapped in a tuple alongside its index.
May receive a function or an integer offset.
If an integer `offset` is given, it will index from the given `offset` instead of from zero.
If a `function` is given, it will index by invoking the function for each
element and index (zero-based) of the `vector`.
Runs in linear time.
## Examples
iex> vector = Aja.Vector.new(["foo", "bar", "baz"])
iex> Aja.Vector.with_index(vector)
vec([{"foo", 0}, {"bar", 1}, {"baz", 2}])
iex> Aja.Vector.with_index(vector, 100)
vec([{"foo", 100}, {"bar", 101}, {"baz", 102}])
iex> Aja.Vector.with_index(vector, fn element, index -> {index, element} end)
vec([{0, "foo"}, {1, "bar"}, {2, "baz"}])
"""
@spec with_index(t(val), index) :: t({val, index}) when val: value
@spec with_index(t(val), (val, index -> mapped_val)) :: t(mapped_val)
when val: value, mapped_val: value
def with_index(vector, fun_or_offset \\ 0)
def with_index(%__MODULE__{__vector__: internal}, offset) when is_integer(offset) do
Raw.with_index(internal, offset) |> from_internal()
end
def with_index(%__MODULE__{__vector__: internal}, fun) when is_function(fun, 2) do
Raw.with_index(internal, 0, fun) |> from_internal()
end
@doc """
Takes `amount` random elements from `vector`.
Note that, unless `amount` is `0` or `1`, this function will
traverse the whole `vector` to get the random sub-vector.
If `amount` is more than the `vector` size, this is equivalent to shuffling the `vector`:
the returned vector cannot be bigger than the original one.
See `Enum.random/1` for notes on implementation and random seed.
Runs in linear time (except for `amount <= 1`, which is effective constant time).
## Examples
# Although not necessary, let's seed the random algorithm
iex> :rand.seed(:exrop, {1, 2, 3})
iex> Aja.Vector.new(1..10) |> Aja.Vector.take_random(2)
vec([7, 2])
iex> Aja.Vector.new([:foo, :bar, :baz]) |> Aja.Vector.take_random(100)
vec([:bar, :baz, :foo])
"""
@spec take_random(t(val), non_neg_integer) :: t(val) when val: value
def take_random(%__MODULE__{__vector__: internal}, amount)
when is_integer(amount) and amount >= 0 do
Raw.take_random(internal, amount) |> from_internal()
end
@doc """
Returns a new vector with the elements of `vector` shuffled.
See `Enum.shuffle/1` for notes on implementation and random seed.
## Examples
# Although not necessary, let's seed the random algorithm
iex> :rand.seed(:exrop, {1, 2, 3})
iex> Aja.Vector.new([1, 2, 3]) |> Aja.Vector.shuffle()
vec([3, 1, 2])
iex> Aja.Vector.new([1, 2, 3]) |> Aja.Vector.shuffle()
vec([1, 3, 2])
"""
@spec shuffle(t(val)) :: t(val) when val: value
def shuffle(%__MODULE__{__vector__: internal}) do
# Note: benchmarks suggest that this is already fast without further optimization
internal
|> Raw.to_list()
|> Enum.shuffle()
|> from_list()
end
@doc """
Zips corresponding elements from two vectors into one vector of tuples.
The size of the returned vector is the one of the smallest of the input vectors.
Runs in linear time.
iex> Aja.Vector.zip(Aja.Vector.new([1, 2, 3]), Aja.Vector.new([:a, :b, :c]))
vec([{1, :a}, {2, :b}, {3, :c}])
iex> Aja.Vector.zip(Aja.Vector.new(0..100), Aja.Vector.new([:a, :b, :c]))
vec([{0, :a}, {1, :b}, {2, :c}])
"""
@spec zip(t(val1), t(val2)) :: t({val1, val2}) when val1: value, val2: value
def zip(vector1, vector2)
def zip(%__MODULE__{__vector__: internal1}, %__MODULE__{__vector__: internal2}) do
Raw.zip(internal1, internal2) |> from_internal()
end
@doc """
Zips corresponding elements from two vectors into a new vector,
transforming them with the `zip_fun` function as it goes.
The corresponding elements from each vector are passed to the
provided 2-arity `zip_fun` function in turn.
Runs in linear time.
iex> Aja.Vector.zip_with(Aja.Vector.new([1, 2, 3]), Aja.Vector.new([:a, :b, :c]), &{&2, &1})
vec([a: 1, b: 2, c: 3])
iex> Aja.Vector.zip_with(Aja.Vector.new(0..100), Aja.Vector.new([:a, :b, :c]), &{&2, &1})
vec([a: 0, b: 1, c: 2])
"""
@spec zip_with(t(val1), t(val2), (val1, val2 -> val3)) :: t(val3)
when val1: value, val2: value, val3: value
def zip_with(vector1, vector2, zip_fun)
def zip_with(%__MODULE__{__vector__: internal1}, %__MODULE__{__vector__: internal2}, zip_fun)
when is_function(zip_fun, 2) do
Raw.zip_with(internal1, internal2, zip_fun) |> from_internal()
end
@doc """
Opposite of `zip/2`. Extracts two-element tuples from the given `vector` and groups them together.
It takes a `vector` with elements being two-element tuples and returns a tuple with two vectors,
each of which is formed by the first and second element of each tuple, respectively.
This function fails unless `vector` only contains tuples with exactly two elements in each tuple.
Runs in linear time.
iex> {vector1, vector2} = Aja.Vector.new([{1, :a}, {2, :b}, {3, :c}]) |> Aja.Vector.unzip()
iex> vector1
vec([1, 2, 3])
iex> vector2
vec([:a, :b, :c])
"""
@spec unzip(t({val1, val2})) :: {t(val1), t(val2)} when val1: value, val2: value
def unzip(%__MODULE__{__vector__: internal}) do
{internal1, internal2} = Raw.unzip(internal)
{from_internal(internal1), from_internal(internal2)}
end
# Private functions
defp from_list([]), do: from_internal(@empty_raw)
defp from_list(list), do: Raw.from_list(list) |> from_internal()
defimpl Inspect do
import Inspect.Algebra
def inspect(vector, opts) do
opts = %Inspect.Opts{opts | charlists: :as_lists}
concat(["vec(", Inspect.List.inspect(Aja.Vector.to_list(vector), opts), ")"])
end
end
defimpl Enumerable do
def count(vector) do
{:ok, Aja.Vector.size(vector)}
end
def member?(%Aja.Vector{__vector__: internal}, value) do
{:ok, Raw.member?(internal, value)}
end
def slice(%Aja.Vector{__vector__: internal}) do
size = Aja.Vector.Raw.size(internal)
{:ok, size,
fn start, length -> Aja.Vector.Raw.slice(internal, start, start + length - 1) end}
end
def reduce(%Aja.Vector{__vector__: internal}, acc, fun) do
# TODO investigate best way to warn
# flag it?
# IO.warn(
# "Enum has sub-optimal performance for Aja.Vector, use Aja.Enum (see https://hexdocs.pm/aja/Aja.Enum.html)"
# )
internal
|> Aja.Vector.Raw.to_list()
|> Enumerable.List.reduce(acc, fun)
end
end
defimpl Collectable do
alias Aja.Vector.Raw
def into(%Aja.Vector{__vector__: internal}) do
{[],
fn
acc, {:cont, value} -> [value | acc]
acc, :done -> done(internal, acc)
_acc, :halt -> :ok
end}
end
defp done(internal, acc) do
new_internal = Raw.concat_list(internal, :lists.reverse(acc))
%Aja.Vector{__vector__: new_internal}
end
end
if Code.ensure_loaded?(Jason.Encoder) do
defimpl Jason.Encoder do
def encode(vector, opts) do
vector |> Aja.Vector.to_list() |> Jason.Encode.list(opts)
end
end
end
end
