From: Gavin Sinclair <gsinclair@...>
Date: 2004-06-02T17:15:39+09:00
Subject: Re: What is the equivalent of Python's '%s' % 'MyString'?

> nobu.nokada@softhome.net wrote in message
> news:<200406020151.i521pOHY005774@sharui.nakada.niregi.kanuma.tochigi.jp>...
>> Hi,
>>
>> At Wed, 2 Jun 2004 03:43:42 +0900,
>> Sam Sungshik Kong wrote in [ruby-talk:102028]:
>> > s = "My name is %(name)s and my age is %(age)d." % {"name": "Sam",
>> "age": 34}
>>
>> > I know that ruby has "#{name}" expression.
>> > But that requires a variable named "name" in advance.
>> > I want to bind the format string and data later.
>>
>> I proposed that feature once in [ruby-dev:16351], though
>> rejected, but still I think that it would be useful for I18N.
>> Is it worth for RCR?
>
> Do you have an example on how would you use this?  I ask because I would
> also vote strongly against it.
>
> One of the things that I really loved about ruby while learning it was
> its "#{}" syntax, as it seemed to me a much more consistent way of
> achieving what sprintf, $, %, etc. have been trying for years to
> achieve in languages like C, perl, python, etc.

Incorrect thinking, I'm afraid.  printf and friends are better than #{}
for *formatted* printing; i.e. specifying field widths, precision, and so
on.  In fact, #{} doesn't even attempt to do formatting.  So there's room
in the world for both.

An example:

  format = " %-25(name)s | %5(age)d | %10.2(salary)f \n"
  records.each do |r|
    printf format, :name => r.name, :age => r.age, :salary => r.salary
  end

That's superior to the existing printf capabilities because it's clearer
and the order of the parameters are independent of the format.

Cheers,
Gavin