Ruby: auto-quote string, not other data, when writing to a file?

Question

i'm writing a small library that writes data out to a file. some of the data is strings, some of it is not - things like boolean (true/false) values...

when I have a string for data, I want to write the string to the file with quotes around it. so a string like "this is a string of data" would be written to the file with the quotes around it.

when i have other types of data, like a boolean, I want to write the boolean value to the file without quotes around it. so, false would be written as false - no quotes around it.

is there a way to automatically quote / not quote the value of a variable, depending on whether or not the variable holding the value is a string, when writing to a file?

Answer 1

Have you tried using kind_of?.

Example: variable.kind_of? String

Answer 2

This is one way to do it:

if myvar.class == String
  #print with quotes
else
  #print value
end

Answer 3

Simplest is #inspect

--------------------------------------------------------- Object#inspect
     obj.inspect   => string
------------------------------------------------------------------------
     Returns a string containing a human-readable representation of
     _obj_. If not overridden, uses the +to_s+ method to generate the
     string.

        [ 1, 2, 3..4, 'five' ].inspect   #=> "[1, 2, 3..4, \"five\"]"
        Time.new.inspect                 #=> "Wed Apr 09 08:54:39 CDT 2003"

You can test it out in IRB.

irb> "hello".inspect
#=> "\"hello\""
irb> puts _
"hello"
#=> nil
irb> true.inspect
#=> "true"
irb> puts _
true
#=> nil
irb> (0..10).to_a.inspect
#=> "[0,1,2,3,4,5,6,7,8,9,10]"
irb> puts _
[0,1,2,3,4,5,6,7,8,9,10]
#=> nil

But for general types, you might want to consider YAML or JSON.

Answer 4

Supposing that your data is of textual type, then doing

data.match(/true|false/).nil? ?  "'#{data}'" : data

should be what you want.