What does %w(array) mean?

I'm looking at the documentation for FileUtils. I'm confused by the following line:

FileUtils.cp %w(cgi.rb complex.rb date.rb), '/usr/lib/ruby/1.6'

What does the %w mean? Can you point me to the documentation?

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%w(foo bar) is a shortcut for ["foo", "bar"] . Meaning it's a notation to write an array of strings separated by spaces instead of commas and without quotes around them. You can find a list of ways of writing literals in zenspider's quickref.

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I think of %w() as a "word array" - the elements are delimited by spaces.

There are other % literals:

%r() is another way to write a regular expression.

%q() is another way to write a single-quoted string (and can be multi-line, which is useful)

%Q() gives a double-quoted string

%x() is a shell command

%i() gives an array of symbols (Ruby >= 2.0.0)

%s() turns foo into a symbol ( :foo )

I don't know any others, but there may be some lurking around in there...

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There is also %s that allows you to create any symbols, for example:

%s|some words|          #Same as :'some words'
%s[other words]         #Same as :'other words'
%s_last example_        #Same as :'last example'

Since Ruby 2.0.0 you also have:

%i( a b c )   # => [ :a, :b, :c ]
%i[ a b c ]   # => [ :a, :b, :c ]
%i_ a b c _   # => [ :a, :b, :c ]
# etc...

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