Kernel.-exclamation-mark
You're seeing just the macro
-exclamation-mark
, go back to Kernel module for more information.
Boolean "not" operator.
Receives any value (not just booleans) and returns true
if value
is false
or nil
; returns false
otherwise.
Not allowed in guard clauses.
Examples
iex> !Enum.empty?([])
false
iex> !List.first([])
true