ExArray

A wrapper module for Erlang's array.

Installation

Requires Elixir v1.14+:

defdepsdo[{:ex_array,"~> 1.0"}]end

Documentation can be found at: https://hexdocs.pm/ex_array.

Usage

Initialization

Without options, ExArray fallbacks on:

• size: 0
• default: nil
• fixed: false

ExArray.new()#=> #ExArray<[], fixed=false, default=nil>ExArray.new(5)#=> #ExArray<[nil, nil, nil, nil, nil], fixed=true, default=nil>

You can provide options to change defaults:

ExArray.new(size: 5,default: 0,fixed: false)#=> #ExArray<[0, 0, 0, 0, 0], fixed=false, default=0>

Note: When you specify a size, the array is automatically fixed.

Setter

arr=ExArray.new(size: 5,default: 0,fixed: false)arr=ExArray.set(arr,1,"Hello")#=> #ExArray<[0, "Hello", 0, 0, 0], fixed=false, default=0>ExArray.reset(arr,1)#=> #ExArray<[0, 0, 0, 0, 0], fixed=false, default=0>

Getter

arr=ExArray.new()|>ExArray.set(1,"Hello")ExArray.get(arr,0)#=> nilExArray.get(arr,1)#=> "Hello"ExArray.size(arr)#=> 2

Conversions

arr=ExArray.new(3)|>ExArray.set(1,"Hello")ExArray.to_list(arr)#=> [nil, "Hello", nil]ExArray.sparse_to_list(arr)#=> ["Hello"]ExArray.to_orddict(arr)#=> [{0, nil}, {1, "Hello"}, {2, nil}]ExArray.sparse_to_orddict(arr)#=> [{1, "Hello"}]

You can also build an ExArray from existing data, or unwrap it back to an Erlang :array:

ExArray.from_list(["a","b","c"])#=> #ExArray<["a", "b", "c"], fixed=false, default=nil>ExArray.from_orddict([{0,"a"},{2,"c"}])#=> #ExArray<["a", nil, "c"], fixed=false, default=nil>arr=ExArray.from_list([1,2,3])ExArray.to_erlang_array(arr)#=> {:array, 3, 10, nil, {1, 2, 3, nil, nil, nil, nil, nil, nil, nil}}

Iteration

ExArray exposes the same map/foldl/foldr helpers as Erlang's :array, plus their sparse_* counterparts that skip default-valued entries:

arr=ExArray.new(size: 4)|>ExArray.set(1,"1")|>ExArray.set(3,"3")ExArray.map(arr,fnindex,value->{index,value}end)#=> #ExArray<[{0, nil}, {1, "1"}, {2, nil}, {3, "3"}], fixed=true, default=nil>ExArray.sparse_foldl(arr,[],fnindex,value,acc->[{index,value}|acc]end)#=> [{3, "3"}, {1, "1"}]

Resizing and fixedness

arr=ExArray.new(5)|>ExArray.set(1,"1")arr|>ExArray.relax()|>ExArray.is_fix()#=> falsearr|>ExArray.resize()|>ExArray.size()#=> 2ExArray.equal?(ExArray.from_list([1,2]),ExArray.from_list([1,2]))#=> true

Protocols

ExArray implements the Access, Enumerable, Collectable, and Inspect protocols, so it works with Elixir's standard tooling.

Access

arr=ExArray.from_list(["a","b","c"])arr[1]#=> "b"get_in(arr,[0])#=> "a"{previous,arr}=pop_in(arr,[1])#=> {"b", #ExArray<["a", nil, "c"], fixed=false, default=nil>}update_in(arr,[0],&String.upcase/1)#=> #ExArray<["A", nil, "c"], fixed=false, default=nil>

Access.fetch/2 returns :error when the slot still holds the array's default value; explicitly stored values (including nil and false) are returned as {:ok, value}.

Enumerable

arr=ExArray.from_list([1,2,3,4,5])Enum.count(arr)#=> 5Enum.map(arr,&(&1*2))#=> [2, 4, 6, 8, 10]Enum.slice(arr,1..3)#=> [2, 3, 4]

Collectable

Enum.into/3 appends new values after the existing entries, preserving the target array's default and fixed settings:

Enum.into([4,5],ExArray.from_list([1,2,3]))#=> #ExArray<[1, 2, 3, 4, 5], fixed=false, default=nil>

Acknowledgments

This package is a fork of takscape/elixir-array. The latest commit was in 2014 and the compilation was broken with recent versions of Elixir.