# Integer(nil) versus Float(nil) versus String(nil) **URL:** \ **Category:** Ruby\ **Created:** [August 23, 2006, 10:46pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203 "2006-08-23T22:46:34Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 23, 2006, 10:46pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/1 "2006-08-23T22:46:34Z")
Dear Rubyists, def x() yield rescue :error end [x { Integer(nil) }, x { Float(nil) }, x{ String(nil) }] # =\> [0, :error, “”] Isn’t that a bit inconsistent? Cheers, ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 23, 2006, 11:32pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/2 "2006-08-23T23:32:38Z")
Christoffer S. wrote: > Dear Rubyists, > > def x() yield rescue :error end > > [x { Integer(nil) }, x { Float(nil) }, x{ String(nil) }] > > # =\> [0, :error, “”] > > Isn’t that a bit inconsistent? Is this better? irb(main):003:0\> nil.to\_i =\> 0 irb(main):004:0\> nil.to\_f =\> 0.0 irb(main):005:0\> nil.to\_s =\> “” Cheers ``` robert ``` ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 23, 2006, 11:38pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/3 "2006-08-23T23:38:39Z")
On 8/23/06, Robert K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Is this better? > > irb(main):003:0\> nil.to\_i > =\> 0 > irb(main):004:0\> nil.to\_f > =\> 0.0 > irb(main):005:0\> nil.to\_s > =\> “” Well, I’d say that it confirms that the original case is an inconsistency. – Rick DeNatale My blog on Ruby [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 28, 2006, 9:38pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/4 "2006-08-28T21:38:19Z")
On 8/24/06, David V. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Probably. > > But my Java-addled brain makes me make damn sure nulls / nils don't come anywhere near I expect actual data, like into collections or numbers. If you don't rely on automagical conversion to work, it can't bite you if it doesn't. Just code explicitly. That’s definitely a valid point, but slightly irrelevant. > The to\_foo and #Foo() type conversion methods being different always > confuses the heck of me, which is why I get paranoid around them. Does > anyone have a link to some rationale for and explanation of the difference? Integer/Float are usually considered to be the _strict_ equivalents of to\_i/to\_f. Try to feed them non-number strings and you’ll see. I don’t know anything more about them though. 🙂 Anyway, I was a bit puzzled over these two things on Integer/Float: 1. Them accepting nil at all 2. The (IMHO) inconsistency I can accept both things as they are, since nothing says they should act the way I except them to, but I thought it could be good to bring it up. Cheers, ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 24, 2006, 11:31pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/5 "2006-08-24T23:31:20Z")
Christoffer S. wrote: > Probably. But my Java-addled brain makes me make damn sure nulls / nils don't come anywhere near I expect actual data, like into collections or numbers. If you don't rely on automagical conversion to work, it can't bite you if it doesn't. Just code explicitly. The to\_foo and #Foo() type conversion methods being different always confuses the heck of me, which is why I get paranoid around them. Does anyone have a link to some rationale for and explanation of the difference? David V. ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [August 28, 2006, 10:00pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/6 "2006-08-28T22:00:22Z")
On 8/28/06, Christoffer S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > That’s definitely a valid point, but slightly irrelevant. Well it is your thread but I understand and agree with David that the nil (do not call it null on that list though 😉 in a conversion is troubeling. I read him that way that by banning it a part of your inconsistency will go away, do you agree? > The to\_foo and #Foo() type conversion methods being different always > > > confuses the heck of me, which is why I get paranoid around them. Does > > anyone have a link to some rationale for and explanation of the > > difference? > > Integer/Float are usually considered to be the _strict_ equivalents of > to\_i/to\_f. Are they? So far I have never heared that claim. [module Kernel - RDoc Documentation](http://www.ruby-doc.org/core/classes/Kernel.html#M002003) says the contrary. I do not necessarily think that is good, but that is how it is documented. Try to feed them non-number strings and you’ll see. No you will not, “x”.to\_i Integer(“x”) I don’t > know anything more about them though. 🙂 > > Anyway, I was a bit puzzled over these two things on Integer/Float: > > 1. Them accepting nil at all > 2. The (IMHO) inconsistency > > I can accept both things as they are, since nothing says they should > act the way I except them to, but I thought it could be good to bring > it up. I too hope that behavior will go away. Cheers, > – > Christoffer S. > [http://vemod.net/](http://vemod.net/) Robert – Deux choses sont infinies : l’univers et la bêtise humaine ; en ce qui concerne l’univers, je n’en ai pas acquis la certitude absolue. - Albert Einstein ---
**Author:** ![Christoffer\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/bb73d2/32.png) [@Christoffer\_S](https://www.ruby-forum.com/u/Christoffer_S)\ **Post date:** [September 2, 2006, 8:32pm UTC](https://www.ruby-forum.com/t/integer-nil-versus-float-nil-versus-string-nil/66203/7 "2006-09-02T20:32:56Z")
Hello! On 8/28/06, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > > > > That’s definitely a valid point, but slightly irrelevant. > > Well it is your thread but I understand and agree with David that the nil > (do not call it null on that list though 😉 > in a conversion is troubeling. > I read him that way that by banning it a part of your inconsistency will go > away, do you agree? Yes, I agree. (But the inconsistency is still there.) 🙂 Just for the record, I discovered the behaviour when using FasterCSV (that emits nil for empty cells) and Integer(x) as a kind of assertion. > [module Kernel - RDoc Documentation](http://www.ruby-doc.org/core/classes/Kernel.html#M002003) says the contrary. > I do not necessarily think that is good, but that is how it is documented. When discussing this issue on #ruby-lang the general concensus was that Integer/Float are indeed stricter versions of to\_i/to\_f. The Pickaxe says “A call to Integer will work wonders (and will throw an exception if the input isn’t a well-formed integer)”. I should also note that the documentation for Kernel#Integer in the Pickaxe actually has “Integer(nil) =\> 0” as an example. > Try to feed them non-number strings and you’ll see. > > No you will not, “x”.to\_i Integer(“x”) “x”.to\_i =\> 0 Integer(“x”) # ArgumentError: invalid value for Integer: “x” Isn’t that just what I meant? > > it up. > > I too hope that behavior will go away. Thanks,