Rails - May 2009 - Combine if and do in a single line?

Is there a  way to combine if and do into a single line?

items.each do |item| if current_user.admin?
  #do stuff
end

Thanks!
-- 
Posted via http://www.ruby-forum.com/.

items.each { |item| item.stuff? } if current_user.admin?

On May 27, 6:17 pm, Mario Gr
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Is there a  way to combine if and do into a single line?
>
> items.each do |item| if current_user.admin?
>   #do stuff
> end
>
> Thanks!
> --
> Posted viahttp://www.ruby-forum.com/.

Mario Gr wrote:
> Is there a  way to combine if and do into a single line?
> 
> items.each do |item| if current_user.admin?
>   #do stuff
> end
> 
> Thanks!


Freddy Andersen wrote:
> items.each { |item| item.stuff? } if current_user.admin?
Which you actually COULD write like this too, but I''m not sure if it 
would be considered easily readable:

items.each do |item|
   #do stuff
end if current_user.admin?

The {| | } and the ''do'' syntaxes are interchangeable in all
ways.  More
of a Ruby question than a Rails one.
-- 
Posted via http://www.ruby-forum.com/.

Jonathan Rochkind wrote:
[...]
> The {| | } and the ''do'' syntaxes are interchangeable in
all ways.
Almost.  I''ve run across a couple of cases where one works and the
other
doesn''t -- one creates a Proc and the other doesn''t, or
something like
that.  But that''s vanishingly rare, and 99 times out of 100, you will 
not go wrong to treat them as interchangeable.
> More 
> of a Ruby question than a Rails one.
Yup.

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

On May 30, 7:03 pm, Marnen Laibow-Koser <rails-mailing-l...@andreas-
s.net> wrote:
> Jonathan Rochkind wrote:
>
> [...]
>
> > The {| | } and the ''do'' syntaxes are interchangeable
in all ways.  
>
> Almost.  I''ve run across a couple of cases where one works and the
other
> doesn''t -- one creates a Proc and the other doesn''t, or
something like
> that.  
{} binds more tightly than do..end - in some cases this can lead to
your block being passed to the ''wrong'' method:

def foo(x)
  puts "foo #{block_given?}"
end

def bar
  puts "bar #{block_given?}"
end

running foo bar {} outputs

bar true
foo false

but running

foo bar do
end

outputs

boo false
foo true

Fred
> But that''s vanishingly rare, and 99 times out of 100, you will
> not go wrong to treat them as interchangeable.
>
> > More
> > of a Ruby question than a Rails one.
>
> Yup.
>
> Best,
> --
> Marnen Laibow-Koserhttp://www.marnen.org
> mar...-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
> --
> Posted viahttp://www.ruby-forum.com/.

Frederick Cheung wrote:
> {} binds more tightly than do..end - in some cases this can lead to
> your block being passed to the ''wrong'' method:
Interesting, makes sense.

Personally, that''s one reason I don''t like making method calls
without
parens, or doing anything else that relies on non-obvious 
order-of-evaluation-binding just to save a couple of parens.

foo(  bar {} )
or
foo( bar do
end )

will both do the same thing. Although the latter is kind of weird style, 
if I need a multi-line block for bar, I''d personally just use a 
temporary var instead.

result = bar do
end
foo(result)

But everyone''s got their own style, I guess. Of course you COULD use 
{||} with multi-lines too, but it would also be stylistically weird in 
my opinion in that case.

foo bar {|a|
   stuff
   more stuff
   }

That''s just weird. And if I DID it, I''d still want to put
parens in
around foo''s argument, which would make it even weirder looking.

Jonathan
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