From: Simon Krahnke <overlord@...>
Date: 2009-10-23T03:35:09+09:00
Subject: Re: Tip du jour: no need to chomp before to_i

* Robert Klemme <shortcutter@googlemail.com> (2009-10-20) schrieb:

> On 20.10.2009 00:49, Simon Krahnke wrote:
>> * Robert Klemme <shortcutter@googlemail.com> (2009-10-13) schrieb:
>>
>>> Basically Integer applies the same semantics as the Ruby parser while
>>> #to_i just grabs the first sequence of digits, treats it as a decimal
>>> number and turns it into an int. If there is no such sequence it falls
>>> back to 0.
>>
>> A little correction: to_i is passed the radix, which by default is 10.
>
> Thanks for correcting me!
>
>> It will return zero if the first character is not the set of digits for
>> that radix, otherwise it will turn the run of digits at the front of the
>> string into an integer according to the radix.
>
> You meant to say "the first _non whitespace_ character". :-)

True. Whitespace at the start of the string seems to be ignored, but is
a stopper everywhere else.

It was complicated enough the way I wrote it. I looked for the ri
documentation on to_i, but all the standard library ri docs seem to be
gone on my computer, strange.

I suppose the code is like this, only better:

def to_i radix=10
  s = 0
  s += 1 while self[s,1] == "\s"
  (s...length).inject(0) | val, i |
    d = self[i,1] # wah!
    next val if d == '_'
    digit = radix_digit(d, radix)
    break val if digit < 0
    val *= radix
    val += digit
  end
end

mfg,                    simon .... l