From: Robert Klemme <bob.news@...>
Date: 2004-06-02T21:28:39+09:00
Subject: Re: What is the equivalent of Python's "%s" % "MyString"?


"Kristof Bastiaensen" <kristof@vleeuwen.org> schrieb im Newsbeitrag
news:pan.2004.06.02.10.45.26.409952@vleeuwen.org...
> Hi,
>
> On Wed, 02 Jun 2004 08:47:30 +0200, Robert Klemme wrote:
> > def myformat(str, hash)
> >   str.gsub( %r{%\((\w+)\)} ) {hash[$1]}
> > end
> >
> >>> myformat("My name is %(name)s and my age is %(age)d.", "name" =>
"Sam",
> > "age" => 34)
> > => "My name is Sams and my age is 34d."
>
> I don't think that's the output he wanted.  He wanted
> to have de value of %(name)s converted to a string,
> and %(age)d to a number  (see my other post for an
> implementation).

Quite easy to fix:

def myformat(str, hash)
  str.gsub( %r{%\((\w+)\)(.)?} ) do
    val = hash[$1]

    case $2
      when 'd'
        val.to_i
      when nil, 's'
        val.to_s
      else
        val
    end
  end
end

>> myformat("My name is %(name)s and my age is %(age)d.", "name" => "Sam",
"age" => 34)
=> "My name is Sam and my age is 34."

Or even more OO and in fact using less LOC:

CONV = Hash.new( lambda {|x| x} ).update( {
  'd' => lambda {|x| x.to_i }
} )

def myformat2(str, hash)
  str.gsub( %r{%\((\w+)\)([dsi])?} ) { CONV[$2].call hash[$1] }
end

>> myformat2("My name is %(name)s and my age is %(age)d.", "name" =>
"Sam", "age" => 34)
=> "My name is Sam and my age is 34."

Regards

    robert