# Re: ruby equivalent PHP function is\_numeric? **URL:** \ **Category:** Ruby\ **Created:** [November 17, 2006, 7:25pm UTC](https://www.ruby-forum.com/t/re-ruby-equivalent-php-function-is-numeric/76349 "2006-11-17T19:25:03Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [November 17, 2006, 7:25pm UTC](https://www.ruby-forum.com/t/re-ruby-equivalent-php-function-is-numeric/76349/1 "2006-11-17T19:25:03Z")
From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On > It really is too bad that String.to\_f does not throw an exception - or > at least return NaN - when the string is not a number. Float( mystring ) does raise an exception, however. ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [November 17, 2006, 8:33pm UTC](https://www.ruby-forum.com/t/re-ruby-equivalent-php-function-is-numeric/76349/2 "2006-11-17T20:33:18Z")
On 11/17/06, Gavin K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On > > > It really is too bad that String.to\_f does not throw an exception - or > > at least return NaN - when the string is not a number. > > Float( mystring ) > does raise an exception, however. hmm, I’m new to Ruby too, so I tried this in irb. irb(main):001:0\> muppet = “3.14” =\> “3.14” irb(main):002:0\> muppet.to\_f =\> 3.14 irb(main):003:0\> muppet =\> “3.14” irb(main):004:0\> penguin = “banana” =\> “banana” irb(main):005:0\> penguin.to\_f =\> 0.0 irb(main):006:0\> Float(muppet) =\> 3.14 irb(main):007:0\> Float(penguin) ArgumentError: invalid value for Float(): “banana” from (irb):7:in `Float’ from (irb):7 from :0 irb(main):008:0\> exit I think String#to\_f should probably throw an exception too. actually, I think whatever the behavior of the two methods is, it should probably be the same in either case. otherwise you end up with the kind of API where you have thirty different methods of doing the same thing, but only two of them work, and of the two that work, neither of them work all the time. it’s like, you have Perl’s “more than one way to do it” and Python’s “only one way to do it” and you have to be careful about letting these creatures mate, it’s kind of a mad scientist situation, you could end up with a monster like, “there’s more than one way to do it, but only one of them actually works, and which one it is varies unpredictably.” ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [November 19, 2006, 7:41pm UTC](https://www.ruby-forum.com/t/re-ruby-equivalent-php-function-is-numeric/76349/3 "2006-11-19T19:41:08Z")
On Sat, Nov 18, 2006 at 04:31:14AM +0900, Giles B. wrote: > irb(main):001:0\> muppet = “3.14” > =\> 3.14 > kind of API where you have thirty different methods of doing the same > thing, but only two of them work, and of the two that work, neither of > them work all the time. > > it’s like, you have Perl’s “more than one way to do it” and Python’s > “only one way to do it” and you have to be careful about letting these > creatures mate, it’s kind of a mad scientist situation, you could end > up with a monster like, “there’s more than one way to do it, but only > one of them actually works, and which one it is varies unpredictably.” Nah. Integer( ) works the same way. Think about Float( ) and Integer( ) vs. to\_i and to\_f being sort of like #to\_int vs. #to\_i. to\_i is like, I want an int out of this, whether this string is an int or not. Integer is like “I have an integer, it just happens to be current represented as a string.”