Ok, granted that I’m pretty new to ruby, but this seems odd to me:
irb(main):001:0> x = [1,2,3]
=> [1, 2, 3]
irb(main):002:0> x.delete 2
=> 2
irb(main):003:0> x
=> [1, 3]
With this behavior, wouldn’t “delete!” be a more appropriate name?
On Jul 7, 2010, at 9:01 AM, Andrew W. wrote:
Ok, granted that I’m pretty new to ruby, but this seems odd to me:
irb(main):001:0> x = [1,2,3]
=> [1, 2, 3]
irb(main):002:0> x.delete 2
=> 2
irb(main):003:0> x
=> [1, 3]With this behavior, wouldn’t “delete!” be a more appropriate name?
Read
http://dablog.rubypal.com/2007/8/15/bang-methods-or-danger-will-rubyist
Is there some kind of interpretation of “delete” that doesn’t imply
the receiving object will be changed?
Compare Hash#update and Hash#merge, for example. Hash#update changes
the receiving hash, which Hash#merge creates a new hash with extra/
overwritten keys from the argument hash. It shouldn’t be too
surprising that Hash#merge! is an alias of Hash#update.
-Rob
Rob B.
[email protected] http://AgileConsultingLLC.com/
[email protected] http://GaslightSoftware.com/
On Wed, Jul 07, 2010 at 10:01:35PM +0900, Andrew W. wrote:
Ok, granted that I’m pretty new to ruby, but this seems odd to me:
irb(main):001:0> x = [1,2,3]
=> [1, 2, 3]
irb(main):002:0> x.delete 2
=> 2
irb(main):003:0> x
=> [1, 3]With this behavior, wouldn’t “delete!” be a more appropriate name?
This came up a few days ago:
David A. Black’s answer covers it nicely, I think.
Dan
On Wed, Jul 7, 2010 at 8:25 AM, Rob B.
[email protected]wrote:
=> [1, 3]
receiving object will be changed?
x = “123”
x.delete ‘2’ # => “13”
x # => “123”
That article is helpful, thanks. Somehow I had exactly that idea in my
mind,
that the ! implies side effects. I was expecting to get back a new array
[1,
3], and that there would be a delete! method defined with the below
behavior. That seems more consistent to me than some vague description
that
! means “dangerous” for some value of “dangerous”. I guess I still have
plenty to learn. Thanks for the link!
On Wed, Jul 7, 2010 at 9:25 AM, Rob B.
On Jul 7, 8:01 am, Andrew W. [email protected] wrote:
With this behavior, wouldn’t “delete!” be a more appropriate name?
On Jul 7, 8:25 am, Rob B. [email protected] wrote:
Is there some kind of interpretation of “delete” that doesn’t imply
the receiving object will be changed?
After some reflection, I can certainly see how you would expect a
bang! there… when working with sets, you often want to manipulate a
set to form a different one.
guests = [‘[email protected]’, ‘[email protected]’, ‘[email protected]’,
‘me’]
invitations_to_send = guests.delete(‘me’)
and in fact there are enumerable operators that work that way…
guest_emails = [‘[email protected]’, ‘[email protected]’,
‘[email protected]’, ‘me’]
guests = guest_emails.map{|email| Person.find_by_email( email ) }
whereas
guest_emails.map!{|email| Person.find_by_email( email ) }
So, yes, inconsistent. Sorry, not much that can be done now… 
The way to do this would be …
invitations_to_send = guests - [‘me’]
or just overwrite delete for your app…
jw
Johnathon W.
Web Application Consultant