# Return in iterator in lambda **URL:** \ **Category:** Ruby\ **Created:** [June 2, 2009, 10:06pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368 "2009-06-02T22:06:37Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 2, 2009, 10:06pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/1 "2009-06-02T22:06:37Z")
I want to create a conditional mathematical function as a lambda structure. Therefore it may be the case that inside an iterative loop, the result of the function is known and should be returned. By implementing this it causes trouble. The test code I created looks like: func = lambda do for z in [1,2,3] return 2 end “something” end puts func.call puts “after call” This results in a LocalJumpError (Ruby 1.8.6 and 1.8.7). In ruby 1.9 it works as expected. Is there a proper way of creating a function like this in ruby \< 1.9? Regards, Benjamin ---
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 2, 2009, 10:53pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/2 "2009-06-02T22:53:41Z")
On Tue, Jun 2, 2009 at 10:06 PM, Benjamin Ter kuile [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > “something” > end > puts func.call > puts “after call” > > This results in a LocalJumpError (Ruby 1.8.6 and 1.8.7). In ruby 1.9 it > works as expected. Is there a proper way of creating a function like > this in ruby \< 1.9? > Yes there is! > Strange you did not ask how though 😉 > Well I’ll tell you anyway… s/return/break/ HTH Robert > Regards, > > ## Benjamin > > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). – Toutes les grandes personnes ont d’abord été des enfants, mais peu d’entre elles s’en souviennent. All adults have been children first, but not many remember. [Antoine de Saint-Exupéry] ---
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 2, 2009, 10:56pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/3 "2009-06-02T22:56:06Z")
On Tue, Jun 2, 2009 at 10:53 PM, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > end > > Well I’ll tell you anyway… > > s/return/break/ But why did you put something there, now it does not work anymore ☹ Sorry did not see lambda f do …each do break 2 end || something end > – > Toutes les grandes personnes ont d’abord été des enfants, mais peu > d’entre elles s’en souviennent. > > All adults have been children first, but not many remember. > > [Antoine de Saint-Exupéry] – Toutes les grandes personnes ont d’abord été des enfants, mais peu d’entre elles s’en souviennent. All adults have been children first, but not many remember. [Antoine de Saint-Exupéry] ---
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 2, 2009, 11:53pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/4 "2009-06-02T23:53:03Z")
Robert D. wrote: > On Tue, Jun 2, 2009 at 10:53 PM, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > wrote: > > > > �end > > > Well I’ll tell you anyway… > > > > s/return/break/ > > But why did you put something there, now it does not work anymore ☹ > Sorry did not see > > lambda f do > …each do > break 2 > end || > something > end This will not work for structures like: data = Array(1…12) func = lambda do |par| answer = 0.0 for z in data answer += Math.log(z) return 2e22 if answer \> 19 end answer -= data.size\*Math.log10(answer) answer end puts func.call 0.2 puts “after call” I am converting from fortran, which makes it harder to see the easy elegant solution 🙂 The function presented is not the real one, but is more like the one I am trying to implement. ---
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 3, 2009, 12:11am UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/5 "2009-06-03T00:11:19Z")
Benjamin Ter kuile wrote: > “something” > end > puts func.call > puts “after call” > > This results in a LocalJumpError (Ruby 1.8.6 and 1.8.7). In ruby 1.9 it > works as expected. Is there a proper way of creating a function like > this in ruby \< 1.9? Enumerable#find may be more appropriate than #each. This avoids the issue of how to break out of nested blocks. func = lambda do |a| a.find do |z| z if z \>= 1.5 end or “not found” end puts func.call([1,2,3]) puts func.call([0,0.2,0.4]) ---
**Author:** ![bterkuile](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e68b1a/32.png) [@bterkuile](https://www.ruby-forum.com/u/bterkuile)\ **Post date:** [June 3, 2009, 8:19pm UTC](https://www.ruby-forum.com/t/return-in-iterator-in-lambda/169368/6 "2009-06-03T20:19:15Z")
I am not sure what you want to do? Do you want to return, than I think the above might work with some tweaking for the non break case, sorry I was lazy. Or do you just want to break, but than it will not work in Ruby1.9? Please avoid “for” it confuses me, please use each for my poor brain ;). Anyway what about this catch( x ) do values.each do throw your\_value if some\_condition end some more code end Nahh, I guess if you refactor this into methods it will just be simpler 😉 or use Joel’s #find if you can, that might give some clean code too 🙂 Cheers Robert – Toutes les grandes personnes ont d’abord été des enfants, mais peu d’entre elles s’en souviennent. All adults have been children first, but not many remember. [Antoine de Saint-Exupéry]