Map.replace-exclamation-mark
You're seeing just the function
replace-exclamation-mark
, go back to Map module for more information.
Specs
Puts a value under key
only if the key
already exists in map
.
If key
is not present in map
, a KeyError
exception is raised.
Inlined by the compiler.
Examples
iex> Map.replace!(%{a: 1, b: 2}, :a, 3)
%{a: 3, b: 2}
iex> Map.replace!(%{a: 1}, :b, 2)
** (KeyError) key :b not found in: %{a: 1}