Useful (useful v1.13.1)

A Library of Useful functions for building Elixir Apps.

Summary

Functions

atomize_map_keys/1 converts a Map with different keys to a map with just atom keys. Works recursively for nested maps. Inspired by stackoverflow.com/questions/31990134

empty_dir_contents/1 delete all files including any directories recursively in a dir but not the dir itself.

flatten_map/1 flattens a Map of any depth/nesting for easier processing. Deeply nested maps are denoted by "" (double underscore) e.g: %{name: Alex, detail: %{age: 17}} becomes `%{name: Alex, detailage: 17}` this makes it easy to see what the data structure was before flattening. Map keys are converted to Atom for simpler access and consistency. Inspired by: https://stackoverflow.com/questions/39401947/flatten-nested-map

get_in_default/3 Proxies Kernel.get_in/2 but allows setting a default value as the 3rd argument.

remove_item_from_list/2 removes a given item from a list in any position.

stringy_map/1 converts a Map of any depth/nesting into a string. Deeply nested maps are denoted by "__" (double underscore). See flatten_map/1 for more details. Alphabetizes the keys for consistency. See: github.com/dwyl/useful/issues/56

stringify_tuple/1 stringifies a Tuple with arbitrary values. Handy when you want to print out a tuple during debugging.

typeof/1 returns the type of a vairable. Inspired by stackoverflow.com/questions/28377135/check-typeof-variable-in-elixir

Functions

Link to this function

atomize_map_keys(value)

atomize_map_keys/1 converts a Map with different keys to a map with just atom keys. Works recursively for nested maps. Inspired by stackoverflow.com/questions/31990134

Examples

iex> Useful.atomize_map_keys(%{"name" => "alex", id: 1})
%{id: 1, name: "alex"}

iex> Useful.atomize_map_keys(%{"name" => "alex", data: %{ "age" => 17}})
%{name: "alex", data: %{age: 17}}
Link to this function

empty_dir_contents(dir)

empty_dir_contents/1 delete all files including any directories recursively in a dir but not the dir itself.

Very happy for anyone to refactor this function to something pretty.

Link to this function

flatten_map(map)

flatten_map/1 flattens a Map of any depth/nesting for easier processing. Deeply nested maps are denoted by "" (double underscore) e.g: %{name: Alex, detail: %{age: 17}} becomes `%{name: Alex, detailage: 17}` this makes it easy to see what the data structure was before flattening. Map keys are converted to Atom for simpler access and consistency. Inspired by: https://stackoverflow.com/questions/39401947/flatten-nested-map

Examples

iex> map = %{name: "alex", data: %{age: 17, height: 185}}
iex> Useful.flatten_map(map)
%{data__age: 17, data__height: 185, name: "alex"}
Link to this function

get_in_default(map, keys, default \\ nil)

get_in_default/3 Proxies Kernel.get_in/2 but allows setting a default value as the 3rd argument.

Examples

iex> map = %{name: "alex", data: %{age: 17, height: 185}}
iex> Useful.get_in_default(map, [:data, :age])
17
iex> Useful.get_in_default(map, [:data, :iq], 180)
180
iex> Useful.get_in_default(nil, [:unhappy, :path], "Happy!")
"Happy!"
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remove_item_from_list(list, item)

remove_item_from_list/2 removes a given item from a list in any position.

Examples

iex> list = ["They'll", "never", "take", "our", "freedom!"]
iex> Useful.remove_item_from_list(list, "never")
["They'll", "take", "our", "freedom!"]
Link to this function

stringify_map(map)

stringy_map/1 converts a Map of any depth/nesting into a string. Deeply nested maps are denoted by "__" (double underscore). See flatten_map/1 for more details. Alphabetizes the keys for consistency. See: github.com/dwyl/useful/issues/56

Examples

iex> map = %{name: "alex", data: %{age: 17, height: 185}}
iex> Useful.stringify_map(map)
"data__age: 17, data__height: 185, name: alex"
Link to this function

stringify_tuple(arg)

stringify_tuple/1 stringifies a Tuple with arbitrary values. Handy when you want to print out a tuple during debugging.

Examples

iex> tuple = {:name, "alex"}
iex> Useful.stringify_tuple(tuple)
"name: alex"

typeof/1 returns the type of a vairable. Inspired by stackoverflow.com/questions/28377135/check-typeof-variable-in-elixir

Examples

iex> Useful.typeof(:atom)
"atom"

iex> bin = "hello"
iex> Useful.typeof(bin)
"binary"

iex> bitstr = <<1::3>>
iex> Useful.typeof(bitstr)
"bitstring"

iex> Useful.typeof(:true)
"boolean"

iex> pi = 3.14159
iex> Useful.typeof(pi)
"float"

iex> fun = fn (a, b) -> a + b end
iex> Useful.typeof(fun)
"function"

iex> Useful.typeof(&Useful.typeof/1)
"function"

iex> int = 42
iex> Useful.typeof(int)
"integer"

iex> list = [1,2,3,4]
iex> Useful.typeof(list)
"list"

iex> map = %{:foo => "bar", "hello" => :world}
iex> Useful.typeof(map)
"map"

iex> Useful.typeof(nil)
"nil"

iex> pid = spawn(fn -> 1 + 2 end)
iex> Useful.typeof(pid)
"pid"

iex> port = Port.open({:spawn, "cat"}, [:binary])
iex> Useful.typeof(port)
"port"

iex> ref = :erlang.make_ref
iex> Useful.typeof(ref)
"reference"

iex> tuple = {:name, "alex"}
iex> Useful.typeof(tuple)
"tuple"