my %hash = map {($_=>1)} qw(shave the modern way);

UPDATE: Thanks to betterworld for pointing out that, if map didn't already evaluate its mapping block in list context, then the parentheses wouldn't help.

you can shave off two characters by omitting the parentheses.

If you want to omit characters, you can write

my %hash = map $_=>1, qw(shave the modern way);
[download]

Update: I'm sorry, I should have tested this code... thanks to lodin, see below.

(Not to mention the whitespace... but often some more characters make the code more readable.)

I find it quite natural that map uses list context and grep uses scalar context. grep's block evaluates to a boolean value (whether or not to include the element), which is a scalar. map's block evaluates to... well, a list. If this were not the case, the parentheses would not help.

One remark about this "map" solution: Note that this works only once. If you use the hash-slice solution, you can add something to the set several times.

If you want to omit characters, you can write

my %hash = map $_=>1, qw(shave the modern way);
[download]

Interestingly, you can't. If you want to remove the block you need to have

map +($_ => 1), ...
[download]

as => is a comma, so what you actually wrote is equivalent to these two statements below.

my %hash = map $_, 1, qw(shave the modern way);
my %hash = map { $_ } 1, qw(shave the modern way);
[download]

(If you write map ($_ => 1), LIST the "function rule" kicks in and it becomes map($_ => 1), LIST i.e. (map $_, 1), LIST.)

This means that you can write

map f($_) => LIST
[download]

which one could read declaratively as "map the function f onto the list I'm pointing at". Personally though I usually think of map as acting in the other direction, "shifting" of one element at a time from the list.

lodin