Map.update
You're seeing just the function
update
, go back to Map module for more information.
Specs
update( map(), key(), default :: value(), (existing_value :: value() -> new_value :: value()) ) :: map()
Updates the key
in map
with the given function.
If key
is present in map
then the existing value is passed to fun
and its result is
used as the updated value of key
. If key
is
not present in map
, default
is inserted as the value of key
. The default
value will not be passed through the update function.
Examples
iex> Map.update(%{a: 1}, :a, 13, fn existing_value -> existing_value * 2 end)
%{a: 2}
iex> Map.update(%{a: 1}, :b, 11, fn existing_value -> existing_value * 2 end)
%{a: 1, b: 11}