Appends to an array value in a map, creating one if the key does not exist

Turns all string map keys into atoms, leaving existing atoms alone (only top level)

To keep the API consistent also a way to get deep nested values. Works also with Stucts.

Put an arbitrarily deep key into an existing map. Works also with Stucts.

If you want to create lists as values, provide :list as last parameter.

If a value already exists at that level, it is turned into a list

For example:

# it works as expected with empty maps
iex> Prelude.Map.deep_put(%{}, [:a, :b, :c], "0")
%{a: %{b: %{c: "0"}}}

# when provided a deep path, all intermediate items are converted to maps
# this can lead to loss of data, eg:
# a.b.c = 1 is replaced by a map to make path a.b.c.d = 2 possible
iex> Prelude.Map.deep_put(%{a: %{b: %{c: "1"}}}, [:a, :b, :c, :d], "2")
%{a: %{b: %{c: %{d: "2"}}}}

# to collect values in a list, provide :list as last parameter.
iex> Prelude.Map.deep_put(%{a: %{b: %{c: "1"}}}, [:a, :b, :c, :d], "2", :list)
%{a: %{b: %{c: %{d: ["2"]}}}}

# to collect values in a list, provide :list as last parameter.
iex> Prelude.Map.deep_put(%{a: %{b: %{c: ["1"]}}}, [:a, :b, :c], "2", :list)
%{a: %{b: %{c: ["2", "1"]}}}

Remove a map key arbitrarily deep in a structure, similar to put_in Works also with Stucts.

For example:

iex> a = %{a: %{b: %{c: %{d: 1, e: 1}}}}
...> Prelude.Map.del_in(a, [:a, :b, :c, :d])
%{a: %{b: %{c: %{e: 1}}}}

Group a map by an array of keys

Provide a list of maps, and a list of keys to group by. All maps must have all the group_by fields, other fields can vary.

For example:

iex> Prelude.Map.group_by(
...>  [%{name: "stian", group: 1, cat: 2},
...>   %{name: "per",   group: 1, cat: 1}],
...>  [:group, :cat])
%{1 =>
  %{1 => [%{cat: 1, group: 1, name: "per"}],
    2 => [%{cat: 2, group: 1, name: "stian"}] } }

Turns all atom map keys into strings, leaving existing strings alone (only top level)

Switch the keys with the values in a map

Converts strings to atoms, but leaves existing atoms alone