Re: [Nolug] Evo and Outlook

On Sat, 2003-07-12 at 03:57, Mark A. Hershberger wrote:
> Ron Johnson <ron.l.johnson@cox.net> writes:
>
> > I'm slightly above newbie regarding REs, and, IMHO, they *are*
> > line noise. Powerful line noise.
>
> Some things are virtually impossible w/o regular expressions.
> Perl-style REs have been incorporated into many languages and tools
> (by virtue of the pcre library). PHP, Python, Exim and others are
> all beneficiaries.

Possible in Python, but takes an aggravating amount of 3GL coding.

> Consider Regular Expressions a mini-language that you can learn once
> and use in lots of different places. There's the idiosyncrasies that
> come with different dialects (sed's REs are different in annoying
> ways), but if you've got the language the dialects aren't that
> difficult.
>
> > I've tried learning Perl, but the pain threshold is so much lower
> > for Python. Writing something to, for example, go thru a directory
> > converting all spaces in filenames is much shorter in Perl than
> > in Python, but a Python newbie who knows how to program (but has
> > not joined The Unix Cult) would understand the code, whereas s/he
> > would be baffled by the Perl code.
>
> Perl:
>
> for(<*>) {if(/ +/) {$o=$_;s/ +/_/g;rename $o,$_}}

Let's make that a non-1-liner:

for(<*>)
{
    if(/ +/)
    {
        $o=$_;
        s/ +/_/g;
        rename $o,$_
    }
}

The implicit assumptions in every line except the braces lines makes
this hard to read unless you grok REs and know Perl's implicit
assumptions.

> Python:
>
> for file in os.listdir("."):
>
> if file.find(" ") != -1:
>
> rename file, re.sub(" ", ".", file)

Tweaked to do recursive filename changing:

import os, re, os.path
def each_dir(arg, dirname, names):
  for file in names:
    file1 = os.path.join(dirname, file)
    if os.path.isfile(file1) and (file.find(' ') != -1):
      os.rename(file1, os.path.join(dirname, re.sub(' ', '_', file)))
os.path.walk('.', each_dir, '')

> By the way, I don't know Python, I just pick up new languages. Lisp
> is the hardest one I've had to pick up, but also, in some ways, the
> most powerful.

> In other ways, Perl is the most powerful. CPAN is an amazing resource
> an no other language comes close to that kind of utility.

Is there any documentation for the functions in CPAN similar to
those of the standard Python library?

-- 
+-----------------------------------------------------------+
| Ron Johnson, Jr.     Home: ron.l.johnson@cox.net          |
| Jefferson, LA  USA   http://members.cox.net/ron.l.johnson |
|                                                           |
| 4 degrees from Vladimir Putin
+-----------------------------------------------------------+
___________________
Nolug mailing list
nolug@nolug.org