This module provides a number of list utility functions, all of which take an initial code block to control their behaviour. They are variations on similar core perl or List::Util functions of similar names, but which use the block to control their behaviour. For example, the core Perl function sort takes a list of values and returns them, sorted into order by their string value. The sort_by function sorts them according to the string value returned by the extra function, when given each value. WWW: https://metacpan.org/release/List-UtilsBy