From: ara.t.howard@...
Date: 2006-11-18T03:14:41+09:00
Subject: Re: ruby equivalent PHP function is_numeric?

On Sat, 18 Nov 2006, Josselin wrote:

> After reading completely my Ruby book, I cannot find a function equivalent to 
> the PHP  is_numeric? to test a String
>
> myString.is_numeric?   (check only digits and dot character)   =>  return 
> true or false
>
> does it exist ? or it's more complicated than that ? (need to build a 
> regex... ?)
>
> thanks
>
> joss



   harp:~ > cat a.rb
   def is_numeric?(n) Float n rescue false end

   args =
     1.2345,
     12345678987654321,
     0,
     0.0,
     ".001",
     123435.12345,
     "123435.",
     "1.50130937545297e+68",
     "a",
     "a42",
     "42a",
     1_2_3.42,
     "1_2_3.42",
     "_1_2_3_.42_",
     "__1__2_3_.42__"

   args.each{|a| puts "is_numeric?(#{ a.inspect }) #=> #{ is_numeric? a }"}



   harp:~ > ruby a.rb
   is_numeric?(1.2345) #=> 1.2345
   is_numeric?(12345678987654321) #=> 1.23456789876543e+16
   is_numeric?(0) #=> 0.0
   is_numeric?(0.0) #=> 0.0
   is_numeric?(".001") #=> 0.001
   is_numeric?(123435.12345) #=> 123435.12345
   is_numeric?("123435.") #=> 123435.0
   is_numeric?("1.50130937545297e+68") #=> 1.50130937545297e+68
   is_numeric?("a") #=> false
   is_numeric?("a42") #=> false
   is_numeric?("42a") #=> false
   is_numeric?(123.42) #=> 123.42
   is_numeric?("1_2_3.42") #=> 123.42
   is_numeric?("_1_2_3_.42_") #=> false
   is_numeric?("__1__2_3_.42__") #=> false



-a
-- 
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