Map with &:method_name

[Oliver Saunders]

I see this a lot but it doesn't work for me in IRB. Is a gem required or
something?

[1,2,3].map(&:to_s)

TypeError: wrong argument type Symbol (expected Proc)
from (irb):2

 

[ara.t.howard]

I see this a lot but it doesn't work for me in IRB. Is a gem
required or
something?

[1,2,3].map(&:to_s)

TypeError: wrong argument type Symbol (expected Proc)
from (irb):2

it's rails - basically


class Symbol
def to_proc
sym = self
lambda{|obj| obj.send sym}
end
end

a @ http://codeforpeople.com/

 

[Rick DeNatale]

[Note: parts of this message were removed to make it a legal post.]

On Jul 10, 2008, at 3:11 PM, Oliver Saunders wrote:

I see this a lot but it doesn't work for me in IRB. Is a gem required or

something?

[1,2,3].map(&:to_s)

TypeError: wrong argument type Symbol (expected Proc)

from (irb):2

it's rails - basically


class Symbol
def to_proc
sym = self
lambda{|obj| obj.send sym}
end
end

And it's been picked up in Ruby 1.9, and maybe 1.8.7 as well since the
current draft of the Pickaxe 3rd ed doesn't label it as 1.9 only.

 

[Oliver Saunders]

I see this a lot but it doesn't work for me in IRB. Is a gem
required or
something?

[1,2,3].map(&:to_s)

TypeError: wrong argument type Symbol (expected Proc)
from (irb):2

it's rails - basically


class Symbol
def to_proc
sym = self
lambda{|obj| obj.send sym}
end
end

a @ http://codeforpeople.com/

OK thanks guys. I found the actual definition:

class Symbol
def to_proc
Proc.new { |*args| args.shift.__send__(self, *args) }
end
end