From: Jeppe Jakobsen <jeppe88@...>
Date: 2006-02-13T06:59:22+09:00
Subject: Re: Scanning a string for decimal numbers

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ok, but I think but wouldn't this regex do the same for me?:

/[-+]?\d+\.?\d+/

Except that it will return an array containing my digit?

2006/2/12, Wilson Bilkovich <wilsonb@gmail.com>:
>
> The scan process returns an array of arrays, so:
> digits[0] is an Array containing '24.4'.
> You could do:
> digits.flatten!
> just before digits[0], and get what you expect.
>
>
> On 2/12/06, Jeppe Jakobsen <jeppe88@gmail.com> wrote:
> > Yes that worked, but I intend to convert the digits of my array to
> floats,
> > and I get a NoMethodError on to_f now when I do this:
> >
> > digits[0] =3D digits[0].to_f
> >
> > I don't understand that :-/
> >
> >
> > 2006/2/12, Wilson Bilkovich <wilsonb@gmail.com>:
> > >
> > > Well, that's what I get for dashing off a quick e-mail before dinner.
> > > The last problem Alexis mentioned is caused by the overly-specific
> > > lookahead at the end.  Here's a version that fixes that:
> > >
> > > irb(main):013:0> a =3D '24.5 + 24 + 24. + 24.4.'
> > > =3D> "24.5 + 24 + 24. + 24.4."
> > > irb(main):014:0> a.scan /[-+]?(\d+(?:\.\d+)?)(?=3D[^\d])/
> > > =3D> [["24.5"], ["24"], ["24"], ["24.4"]]
> > > irb(main):015:0>
> > >
> > > One of the characters '-' or '+', optionally
> > > Followed by at least one digit.
> > > Followed by an optional group containing a period, and one or more
> digits.
> > > The capturing group ends when the next character is something other
> > > than a digit.
> > >
> > > The (?:) mess is there so that '24.' doesn't end up with the period o=
n
> the
> > > end.
> > >
> > > On 2/11/06, Jeppe Jakobsen <jeppe88@gmail.com> wrote:
> > > > Seems I accidently got my text marked as a qoute in my last mail, s=
o
> > > I'll
> > > > just send it a again:
> > > >
> > > > Let me see if I got it right then. I'll like to use periods only fo=
r
> my
> > > > decimal numbers. I also need normal integers so 24. being accepted
> won't
> > > > matter. Will this fix the problems you presented?:
> > > > /[-+]?(\d+\.?\d*)(?=3D\s|$)/
> > > >
> > > >
> > > > I don't know if it takes care of the last problem, because I didn't
> > > > understand it.
> > > >
> > > >
> > > > 2006/2/12, Jeppe Jakobsen <jeppe88@gmail.com>:
> > > > >
> > > > > 2006/2/12, Alexis Reigel <mail@koffeinfrei.org>:
> > > > > >
> > > > > > >
> > > > > > > This should handle periods or commas as the separator.
> > > > > > >
> > > > > > > a =3D "24,4 + 55,2 + 55 - 44,0"
> > > > > > >    =3D> "24,4 + 55,2 + 55 - 44,0"
> > > > > > > a.scan /(\d+,?.?\d*)(?=3D\s|$)/
> > > > > > >    =3D> [["24,4"], ["55,2"], ["55"], ["44,0"]]
> > > > > > >
> > > > > >
> > > > > > Some problems here:
> > > > > > - signs are disregarded ("-24,4" becomes "24,4")
> > > > > > - Invalid numbers are accepted: eg. "24,.4" "24,." "24." "24,"
> > > > > > - "." should be escaped. As you used it here, it means "any
> > > character"
> > > > > > (except newline), so many invalid numbers are accepted (e.g.
> > > "24w"...)
> > > > > > - If something different from whitespace follows the number, it
> is
> > > not
> > > > > > or false accepted, e.g. "24.4." becomes "4." instead of "24.4"
> > > > > > - ...
> > > > > >
> > > > > >
> > > > > > Alexis.
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
> > --
> > "winners never quit, quitters never win"
> >
> >
>
>


--
"winners never quit, quitters never win"

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