Hi, I’m looking for cucumber/generators and didn’t understand why use
‘*’ before string on initialize method.
I put it on irb and the result is the same.
class NamedArg
attr_reader :name
def initialize(s)
@name, @type = *s.split(':')
end
Am Freitag, 13. Feb 2009, 01:51:24 +0900 schrieb Jonatas P.:
class NamedArg
def initialize(s) @name, @type = *s.split(’:’)
end
end
Why and where use * before string?
Actually, you use the asterisk in front of an array. The asterisk
makes the array to a list of arguments. Examples:
ary.push [ :a, :b] # pushes an array
ary.push *[ :a, :b] # pushes two symbols
You may even do this:
done = %(exit quit bye)
case str.downcase
when *done then return
end
In your example, the conversion will be done automatically when
the right side is an array. When I code, I write the asterisk
explicitly every time to remind myself what I meant.
It’s not before a String but before an Array. You can see for yourself
by firing up IRB and experimenting a bit with this. The short story is
that it’s called “splash operator” IIRC and it will distribute the Array
across all parameters or local variables. Other example uses are
def foo(a,b,c)
puts a,b,c
end
foo(1,2,3)
ar = [1,2,3]
foo(*ar)
foo(ar) # -> error because you do not provide enough arguments
On Thu, Feb 12, 2009 at 12:22 PM, Bertram S. [email protected]wrote:
when *done then return
end
In your example, the conversion will be done automatically when
the right side is an array. When I code, I write the asterisk
explicitly every time to remind myself what I meant.
All true, except that in this case, it’s in the context of a parallel
assignment statement rather than a method call.