Path: csiph.com!usenet.pasdenom.info!gegeweb.org!eternal-september.org!feeder.eternal-september.org!mx04.eternal-september.org!.POSTED!not-for-mail
From: Gene Wirchenko <genew@ocis.net>
Newsgroups: comp.lang.java.programmer
Subject: Re: need regular expression to replace part of result based on a search pattern
Date: Thu, 12 Jul 2012 09:18:18 -0700
Organization: A noiseless patient Spider
Lines: 41
Message-ID: <ptttv71mt6jf2mog2p2fr7816am6gpka7l@4ax.com>
References: <6aefda61-b66a-4e8f-8634-ef6a95f79c4d@googlegroups.com> <VMednY1XR8zyf2PSnZ2dnUVZ8ridnZ2d@giganews.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
Injection-Info: mx04.eternal-september.org; posting-host="c0a6a1dc41fc92eb7000e57afbd16211"; logging-data="32186"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+EsB6rgDp9OXnpXCVDhao2mkkzGl+cZZo="
X-Newsreader: Forte Agent 4.2/32.1118
Cancel-Lock: sha1:Xl0TkBttKmcoAooBMm08MPTeF3E=
Xref: csiph.com comp.lang.java.programmer:15984

On Thu, 12 Jul 2012 09:42:55 -0500, Leif Roar Moldskred
<leifm@dimnakorr.com> wrote:

>Jimmy <jimmy_please@yahoo.com> wrote:
>> Have been having hard time to come up with the regular expression to replace the following..
>
>Then don't use a regular expression. 
>
>There's a quote by Brian Kernighan that “Debugging is twice as hard as
>writing the code in the first place. Therefore, if you write the code
>as cleverly as possible, you are, by definition, not smart enough to
>debug it.”

     A bit of exaggeration, but not much.

>In other words, if it's not quickly obvious how to write a regular
>expression that does what you want, use something else. Your
>maintenance programmers (often your six-month older self) will thank
>you.

     If you really, really, really have to do it, know that you will
end up with Write-Only code so isolate as much as you can.  Document
it, and hope that you never have to deal with it again.  If you do,
you will appreciate the documentation.

>From the description you've given of the problem, I would think that
>your best bet is to parse your input as a CSV, do the required
>changes, and write it back into a CSV. Easier to write and easier to
>read than a dose of line noise.

     And easier to modify.  What if you later have to also modify
column 4 to always have 'N'?  If your first reaction is negative, then
your code is too complex.

     I write a lot of my code without worrying much about how fast or
elegant it is.  Usually, it is quite fast enough, and it is
maintainable.

Sincerely,

Gene Wirchenko