Testing contents of string for known types

ruby-talk
1

Is there a built-in way to test the contents of a string to try and find
a logical type of data that it might contain? For example, say a string
contains “4.56”. It would be nice to have

“4.56”.inferred_type => Float
"23".inferred_type => Fixnum
"george".inferred_type => String

Thanks,
Carl Youngblood

2

Carl Youngblood wrote:

Is there a built-in way to test the contents of a string to try and
find a logical type of data that it might contain? For example, say a
string contains “4.56”. It would be nice to have

“4.56”.inferred_type => Float
“23”.inferred_type => Fixnum
“george”.inferred_type => String

Something like this, perhaps?

class String
  def inferred_type
    eval(self).class
  rescue
    String
  end
end

p "3.14".inferred_type
p "15".inferred_type
p "george".inferred_type

I’m not sure how robust this is, since it uses eval (if the string
contains the name of a method of String, then the result you get back
will be the class of whatever tha t method returns…).

···

–
Jamis Buck
jgb3@email.byu.edu

ruby -h | ruby -e ‘a=;readlines.join.scan(/-(.)[e|Kk(\S*)|le.l(…)e|#!(\S*)/) {|r| a << r.compact.first };puts “\n>#{a.join(%q/ /)}<\n\n”’