you want to process a number of things? Think foreach or map. You want to turn a bunch of things into a string with a common delimiter? Think join.

But I'm not sure what you want to do: it looks like you start out with a (possibly mixed-case) string in $_ and want an all lower-case *string* ($alldays is a scalar) out, in which case

$alldays = lc $_;
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But supposing you want that array for whatever reason: my $alldays = join " ", map { lc $_ } ($mon, $tue, $wed, $thu, $fri, $sat, $sun);

the map lowercases each of the elements of the array, and the join puts a space in between each member of that array.

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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