Underscore - Usage in Computing - Use in Other Languages

Use in Other Languages

Ruby and Perl use $_ as a special variable described as the “default input and pattern matching space” — any output defaults to that variable, and may be omitted. In Perl, @_ is a special array variable that holds the arguments to a function.

In some languages with pattern matching, such as Standard ML, OCaml, and Haskell, the pattern _ matches any value, but does not perform binding.

In the interactive Python interpreter, the special variable _ holds the result of the previous evaluation.