CODEWITHSUNDEEP
rubycasting
Ybur
Ybur

Reputation: 9

Casting by a variable of class

I can cast a string to float via:

Float("1")

Now I have this:

f = Float

How can I use f to cast a string to float?

Edited

I'm sorry for not being clear.

Here is my scenario:

I'm using Redis DB, via gem redis-rb. Basically redis-db stores values as strings. When I map back values from DB to my objects, I wish to cast them to some primitive types for easy to use.

So I use this:

require 'ostruct'

class Person < OpenStruct

    MAP = { :name => String, :age => Fixnum }

    ##
    # This reads data from DB, and converts them to some "primitive" types
    # for easy use.
    #
    def read
        MAP.each_pair do |sym, cls|
            # read data as string from DB, via key `sym.to_s`
            s = ...
            # now I have `cls`, how can I "cast" `s` to `cls`?
            self[sym] = ???

            # I know I can "iterate" all types by this:
            #
            # if cls.is_a? Float
            #     self[sym] = s.to_f
            # elsif cls.is_a? Fixnum
            #     self[sym] = s.to_i
            # ...
            #
            # But in Python I can just cast `s` to `cls` in one line...
            # So I wonder if there is some way to cast `s` to `cls` in Ruby?
        end
    end # read

end # Person

Saying "for easy use", I mean I want to:

p = Person.new
p.read
# I want to access `age` as an integer, not a string
if p.age +-*/ ...

Upvotes: 0

Views: 111

Answers (2)

Abdul Baig
Abdul Baig

Reputation: 3721

For what I understood from your question you want this:

result = '1'.to_f  #outputs => 1.0

then for string:

result.to_s  #outputs => "1.0"

And you can also do it in one step as well:

'1'.to_f.to_s #outputs => "1.0"

For more about strings and ruby you can see ruby doc

Upvotes: 0

sawa
sawa

Reputation: 168199

You cannot use f to do it. The Float in Float("1") is a method. The Float in f = Float is a class (an object). They are different things.

Upvotes: 2

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