How would a module make the transformation much easier? What would you expect a call to the transform function provided by such a module to look like?

As an aside, using map in void context is frowned on. It is generally considered clearer to use a for statement modifier:

push @{$var1->{$_->{city}}}, $_->{name} for @$var;

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True laziness is hard work

In reply to Re: Data Structure Transformation by GrandFather
in thread Data Structure Transformation by aartist

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