[19107] in Perl-Users-Digest
Perl-Users Digest, Issue: 1302 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Jul 13 18:10:34 2001
Date: Fri, 13 Jul 2001 15:10:15 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Message-Id: <995062214-v10-i1302@ruby.oce.orst.edu>
Content-Type: text
Perl-Users Digest Fri, 13 Jul 2001 Volume: 10 Number: 1302
Today's topics:
Re: Random Numbers... <rsherman@ce.gatech.edu>
regexp question <emdee@DEMUNGEcwcom.net>
Re: regexp question <mbudash@sonic.net>
Re: regexp question (Craig Berry)
Replacing a word in a file (BUCK NAKED1)
Re: Replacing a word in a file <cpryce@pryce.net>
Re: Replacing a word in a file <tore@extend.no>
Re: Replacing a word in a file (Tad McClellan)
Re: Replacing a word in a file <cpryce@pryce.net>
Re: search and replace $ (Joe Smith)
Re: search and replace $ <mdudley@execonn.com>
Shouldn't -e return FALSE instead of UNDEFINED on non-e (pt)
Re: Signal SEGV - What is it? <stumo@bigfoot.com>
Re: Using long integer in PERL <tore@extend.no>
warn() does not use a localized STDERR filehandle, how (nico gianniotis)
Re: Where is MD5 <krahnj@acm.org>
Why is socket timeout not working? <haim.lichaa@intel.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 13 Jul 2001 14:02:40 +0500
From: Robert Sherman <rsherman@ce.gatech.edu>
Subject: Re: Random Numbers...
Message-Id: <3B4EB930.C6D89076@ce.gatech.edu>
TedWeb wrote:
>
> Does perl have a random number generator? If so, how do I use it?
>
> Many thanks,
> TedWeb
perldoc -f rand
perldoc -f srand
------------------------------
Date: Fri, 13 Jul 2001 18:37:11 GMT
From: Matt D <emdee@DEMUNGEcwcom.net>
Subject: regexp question
Message-Id: <chfukt4q0c9u5o157ob2ot20hv3vu23gj5@4ax.com>
there's probably a 'doh! of course!' answer to this, but it's eluding
me at the moment...
i want to capture a keyword and up to 3 words either side of it from a
block of text (keyword could potentially be at the beginning, end or
anywhere in the middle).
my block of text is a single space-delimited list of words.
i can do this:
$text =~ /(\S*\s*\S*\s*\S*\s*)($keyword)(\s*\S*\s*\S*\s*\S*)/i;
$match = "$1$2$3";
which kind of works but it can be very slow on big lists of words.
i'm sure there's a much more efficient way to do it.. can some kind
soul point me in the right direction please?
TIA,
m
------------------------------
Date: Fri, 13 Jul 2001 19:51:47 GMT
From: Michael Budash <mbudash@sonic.net>
Subject: Re: regexp question
Message-Id: <mbudash-887CF8.12515013072001@news.sonic.net>
In article <chfukt4q0c9u5o157ob2ot20hv3vu23gj5@4ax.com>, Matt D
<emdee@DEMUNGEcwcom.net> wrote:
> there's probably a 'doh! of course!' answer to this, but it's eluding
> me at the moment...
>
> i want to capture a keyword and up to 3 words either side of it from a
> block of text (keyword could potentially be at the beginning, end or
> anywhere in the middle).
>
> my block of text is a single space-delimited list of words.
>
> i can do this:
>
> $text =~ /(\S*\s*\S*\s*\S*\s*)($keyword)(\s*\S*\s*\S*\s*\S*)/i;
> $match = "$1$2$3";
>
> which kind of works but it can be very slow on big lists of words.
> i'm sure there's a much more efficient way to do it.. can some kind
> soul point me in the right direction please?
not sure about the speed issue, but this works for me:
undef $match;
if ($text =~ /(\S+\s){0,3}$keyword(\s\S+){0,3}/) {
$match = $&;
}
hth-
--
Michael Budash ~~~~~~~~~~ mbudash@sonic.net
------------------------------
Date: Fri, 13 Jul 2001 21:16:11 -0000
From: cberry@cinenet.net (Craig Berry)
Subject: Re: regexp question
Message-Id: <tkup8rq30etpb0@corp.supernews.com>
Matt D (emdee@DEMUNGEcwcom.net) wrote:
: there's probably a 'doh! of course!' answer to this, but it's eluding
: me at the moment...
:
: i want to capture a keyword and up to 3 words either side of it from a
: block of text (keyword could potentially be at the beginning, end or
: anywhere in the middle).
:
: my block of text is a single space-delimited list of words.
If the block isn't big and exact spacing doesn't need to be maintained,
I'd do it like this:
my $block = 'foo blah barg zneeb foo dribble foo glarb doh foo sneex';
my $kw = 'foo';
my @words = $block =~ /(\w+)/g;
for (my $i = 0; $i < @words; $i++) {
if ($words[$i] eq $kw) {
my $lo = $i - 3;
my $hi = $i + 3;
$lo = 0 if $lo < 0;
$hi = $#words if $hi > $#words;
print join(' ', @words[$lo..$hi]), "\n";
}
}
This grabs every instance of 'foo' and up to three words on either side of
it. Note that overlapping ranges will work properly.
--
| Craig Berry - http://www.cinenet.net/~cberry/
--*-- "Brute force done fast enough looks slick."
| - William Purves
------------------------------
Date: Fri, 13 Jul 2001 14:46:32 -0500 (CDT)
From: dennis100@webtv.net (BUCK NAKED1)
Subject: Replacing a word in a file
Message-Id: <14207-3B4F5018-87@storefull-248.iap.bryant.webtv.net>
Why doesn't the below work? I've tested this for hours, and get no
error; but it doesn't replace. I want to replace one word with another
in a file called $tmpfile.
open(TFILE, "$tmpfile") or die "can't open $tmpfile: $!";
while (<$tmpfile>) {
$tmpfile =~ s/$original/$replacement/ig or print "Cant
replace: $!\n";
};
close TFILE;
What am I doing wrong?
Thanks,
Dennis
------------------------------
Date: Fri, 13 Jul 2001 15:37:01 -0500
From: cp <cpryce@pryce.net>
Subject: Re: Replacing a word in a file
Message-Id: <B774C61D.87F4%cpryce@pryce.net>
in article 14207-3B4F5018-87@storefull-248.iap.bryant.webtv.net, BUCK NAKED1
at dennis100@webtv.net wrote on 07/13/2001 2:46 PM:
> Why doesn't the below work? I've tested this for hours, and get no
> error; but it doesn't replace. I want to replace one word with another
> in a file called $tmpfile.
> open(TFILE, "$tmpfile") or die "can't open $tmpfile: $!";
# filehandle is opened in read only mode.
> while (<$tmpfile>) {
# do you mean while (<TFILE>) { ?
> $tmpfile =~ s/$original/$replacement/ig or print "Cant
> replace: $!\n";
# if $tmpfile was your path, you are trying your search/replace on the SAME
value for each and every line of TFILE
> };
> close TFILE;
>
> What am I doing wrong?
You are not reading the FAQs. This is covered in perlfaq5 'How do I change
one line in a file/delete a line in a file/insert a line in the middle of a
file/append to the beginning of a file?'
It's also covered in chapter 7 of the Perl Cookbook.
cp
------------------------------
Date: Fri, 13 Jul 2001 22:41:18 +0200
From: Tore Aursand <tore@extend.no>
Subject: Re: Replacing a word in a file
Message-Id: <MPG.15b97b5dd6c78cd0989695@news.online.no>
In article <14207-3B4F5018-87@storefull-
248.iap.bryant.webtv.net>, dennis100@webtv.net says...
> Why doesn't the below work?
Because the syntax is _completely_ wrong. :)
> open(TFILE, "$tmpfile") or die "can't open $tmpfile: $!";
Good! Not everyone remember (?) to include the die statement.
> while (<$tmpfile>) {
> $tmpfile =~ s/$original/$replacement/ig or print "Cant
> replace: $!\n";
> };
> close TFILE;
You are using a scalar as a filehandle. That doesn't work.
This should work better;
my $tmpfile = './file.temp';
open(TMPFILE, $tmpfile) || die "$!\n";
while (<TMPFILE>) {
s/$original/$replacement/gi;
}
close(TMPFILE);
--
Tore Aursand - tore@extend.no - www.aursand.no
------------------------------
Date: Fri, 13 Jul 2001 15:57:45 -0400
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: Replacing a word in a file
Message-Id: <slrn9kuklp.o8a.tadmc@tadmc26.august.net>
BUCK NAKED1 <dennis100@webtv.net> wrote:
>Why doesn't the below work? I've tested this for hours,
^^^^^^^^^
You have wasted your time then. Don't do that.
Start with some "good code" and modify it for your needs.
>and get no
>error; but it doesn't replace.
>I want to replace one word with another
>in a file called $tmpfile.
^^^^
^^^^ there's a nice search term...
perldoc -q file
"How do I change one line in a file/delete a line in a
file/insert a line in the middle of a file/append to the
beginning of a file?"
>open(TFILE, "$tmpfile") or die "can't open $tmpfile: $!";
^ ^
^ ^ useless double quotes
open(TFILE, $tmpfile) or die "can't open $tmpfile: $!";
>while (<$tmpfile>) {
while (<TFILE>) { # wants a filehandle, not a string
> $tmpfile =~ s/$original/$replacement/ig or print "Cant
>replace: $!\n";
You are substituting in the $tmpfile variable. What is in the
$tmpfile variable? A filename. Do you want to change the
filename or the file _contents_?
The line from the file is in $_, not in $tmpfile;
Why the "or print" there? it will complain for any line that
does not happen to have a $original in it. Are all data lines
required to match whatever that is?
> };
>close TFILE;
Your program never made any output (because you do not use any
output operators). A program that makes no output is of very
limited value. You probably want a print() in there somewhere.
>What am I doing wrong?
Just about everything it would appear.
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Fri, 13 Jul 2001 16:01:31 -0500
From: cp <cpryce@pryce.net>
Subject: Re: Replacing a word in a file
Message-Id: <B774CBDB.8805%cpryce@pryce.net>
in article MPG.15b97b5dd6c78cd0989695@news.online.no, Tore Aursand at
tore@extend.no wrote on 07/13/2001 3:41 PM:
>> while (<$tmpfile>) {
>> $tmpfile =~ s/$original/$replacement/ig or print "Cant
>> replace: $!\n";
>> };
>> close TFILE;
>
> You are using a scalar as a filehandle. That doesn't work.
> This should work better;
>
> my $tmpfile = './file.temp';
> open(TMPFILE, $tmpfile) || die "$!\n";
> while (<TMPFILE>) {
> s/$original/$replacement/gi;
> }
> close(TMPFILE);
While this is replacing the $_ string nicely, it's not doing anything with
it. Like printing the results to a file. Which it can't do to TMPFILE 'cause
it's opened in read mode.
------------------------------
Date: Fri, 13 Jul 2001 18:29:31 +0000 (UTC)
From: inwap@best.com (Joe Smith)
Subject: Re: search and replace $
Message-Id: <9inemb$14j5$1@nntp1.ba.best.com>
In article <3B4F2FE8.DCEAB8C4@execonn.com>,
Marshall Dudley <mdudley@execonn.com> wrote:
>I don't know if this is a bug, or what, but I am finding it impossible
>to search for a dollar sign and replace it with something else.
>
>I am running perl verison 5.005_03
>
>For instance, with the following code:
>
>$text = "this product cost $5 to purchase\n";
print "Before doing substitution, text='$text'\n";
print "Oops. There is no dollar sign there. Lets try again\n";
$text = 'this product cost $5 to purchase' . "\n";
>$text =~ s/\$/ dollars /;
>print "$text\n";
>If I search for any other character than the "$" it works fine, it just
>messes up with the dollar sign.
The problem was that your example was using $5 as the name of a variable
because the dollarsign was between double quotes. Go back to the
manual and look up "quote-like operators".
>What I am wanting to do in the end is to replace all "$" with "\$" in a
>string so I can use it for a regular expression.
There is a different solution for that. Use qr() or \Q.
s/\Q$string/$replacement/;
-Joe
--
See http://www.inwap.com/ for PDP-10 and "ReBoot" pages.
------------------------------
Date: Fri, 13 Jul 2001 14:54:49 -0400
From: Marshall Dudley <mdudley@execonn.com>
Subject: Re: search and replace $
Message-Id: <3B4F43F9.34567DAF@execonn.com>
DUH. Boy do I feel stupid. The real code the text comes in from a post,
but I was trying to get it to work in a small test script and that is what I
screwed up. Turns out the real problem is that I cannot substute /\\$/ but
have to use /\\\$/ to get \$.
Working now.
Thanks,
Marshall
Joe Smith wrote:
> In article <3B4F2FE8.DCEAB8C4@execonn.com>,
> Marshall Dudley <mdudley@execonn.com> wrote:
> >I don't know if this is a bug, or what, but I am finding it impossible
> >to search for a dollar sign and replace it with something else.
> >
> >I am running perl verison 5.005_03
> >
> >For instance, with the following code:
> >
> >$text = "this product cost $5 to purchase\n";
>
> print "Before doing substitution, text='$text'\n";
> print "Oops. There is no dollar sign there. Lets try again\n";
> $text = 'this product cost $5 to purchase' . "\n";
>
> >$text =~ s/\$/ dollars /;
> >print "$text\n";
>
> >If I search for any other character than the "$" it works fine, it just
> >messes up with the dollar sign.
>
> The problem was that your example was using $5 as the name of a variable
> because the dollarsign was between double quotes. Go back to the
> manual and look up "quote-like operators".
>
> >What I am wanting to do in the end is to replace all "$" with "\$" in a
> >string so I can use it for a regular expression.
>
> There is a different solution for that. Use qr() or \Q.
> s/\Q$string/$replacement/;
>
> -Joe
>
> --
> See http://www.inwap.com/ for PDP-10 and "ReBoot" pages.
------------------------------
Date: 13 Jul 2001 14:30:22 -0700
From: mnemotronic@yahoo.com (pt)
Subject: Shouldn't -e return FALSE instead of UNDEFINED on non-existant file?
Message-Id: <da662010.0107131330.6a7980e2@posting.google.com>
The generic description for the file test operators says they return 1
for TRUE and '' for FALSE. The -e (file exists) does not return FALSE
if the file doesn't exist, it returns UNDEFINED, as do the other -X
operators.
I know I'm picking at nano-nits while rowing upstream amd pissing
into the wind here, but it makes sense (to me) for this operator to
actually return TRUE or FALSE.
Is it possible for -e to ever return the FALSE value ('') ???
------------------------------
Date: Fri, 13 Jul 2001 20:28:28 +0100
From: "Stuart Moore" <stumo@bigfoot.com>
Subject: Re: Signal SEGV - What is it?
Message-Id: <DYH37.26962$WS4.4095278@news6-win.server.ntlworld.com>
Dan Sugalski <dan@tuatha.sidhe.org> wrote in message
news:vVD37.158720$v5.12197549@news1.rdc1.ct.home.com...
> Stuart Moore <stumo@bigfoot.com> wrote:
>
> > Just for the record:
>
> > The error was solved when commenting out a particular line of a hash
definition
> > (as in %hash = (a=>b, ...)
> > The value of this key was from a variable, I changed the lines where this
> > variable value was obtained, so that exactly the same value was obtained in
a
> > slightly different manner (it had to de reference the output of a function
> > pointing to an array and take the first subscript) and it worked. There's
more
> > than one way to do it, but one of them causes a signal fault ;-)
>
> That's really, really bad, and it means something's wrong internally. If you
> can ship the entire program causing the problem off to activestate that
> woul dbe a good thing, since there's a bug in perl somewhere. (If you can
> duplicate the death on another OS that'd be even better)
>
> Did you fork() along the way by any chance?
>
No fork or anything complicated in my code; modules involved were DBI
(connecting to mysql) and CGI. Unfortunately I don't have that version any
longer, didn't think to keep it. If the same happens again, I'll keep a copy.
Stuart
------------------------------
Date: Fri, 13 Jul 2001 22:31:18 +0200
From: Tore Aursand <tore@extend.no>
Subject: Re: Using long integer in PERL
Message-Id: <MPG.15b979049fcb6fe5989694@news.online.no>
In article <3b4ef0c2@news>,
benghua@NOSPAMMING.cyberworks.net.sg says...
> I have an array with big numbers, [...]
Take a look at the Math::* modules in the CPAN directory [1],
especially Math::BigInt.
[1] <URL:http://www.cpan.org/>
--
Tore Aursand - tore@extend.no - www.aursand.no
------------------------------
Date: 13 Jul 2001 13:58:49 -0700
From: nico@arzoon.com (nico gianniotis)
Subject: warn() does not use a localized STDERR filehandle, how come?
Message-Id: <d71d1211.0107131258.586138e3@posting.google.com>
Hi,
Does anyone know why localizing STDERR, before reopening it, causes
unexpected results from warn()? For example,
open(STDERR, ">/tmp/z");
warn "this goes into /tmp/z\n";
close(STDERR);
works as expected and desired.
But:
{
local *STDERR;
open(STDERR, ">/tmp/z");
warn "oops! this comes out the original stderr! why?\n";
print STDERR "however, this goes into /tmp/z as expected\n";
close(STDERR);
}
It would appear that warn() might not use the dynamically scoped value
of the STDERR filehandle directly, but instead might use some cached
version of it?
Is there a way to make this work?
Thanks in advance for any explanations.
nico
------------------------------
Date: Fri, 13 Jul 2001 21:20:39 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: Where is MD5
Message-Id: <3B4F6678.B101EF2@acm.org>
gnari wrote:
>
> In article <1ewgfan.1uylxjh49fmeqN%otto.wyss@bluewin.ch>,
> Otto Wyss <otto.wyss@bluewin.ch> wrote:
>
> [
> Otto: you are still skipping the attribution.
> the attribution is the bit that says 'In article blabla, suchandsuch says:'
> ]
>
> >> >perldoc *MD5*
> >>
> >> personally, i often use lthe command locate for this purpose.
> >> for example: locate MD5.pm
> >> on your system you may have something different, but most have
> >> some way of searching for files
> >>
> >That does not help if the name isn't exactly known. That is one of the
> >biggest problem a nonexpert has to face.
>
> then there is the good old (on unix):
> find perl -e 'print "@INC"' -name '*MD5.pm' -print
>
> or for ALL modules in @INC:
> find perl -e 'print "@INC"' -name '*.pm' -print
You forgot the back quotes.
find `perl -e 'print "@INC"'` -name '*MD5.pm' -print
find `perl -e 'print "@INC"'` -name '*.pm' -print
John
--
use Perl;
program
fulfillment
------------------------------
Date: Fri, 13 Jul 2001 23:59:15 +0300
From: "Haim Lichaa" <haim.lichaa@intel.com>
Subject: Why is socket timeout not working?
Message-Id: <9innfd$d4m@news.or.intel.com>
I'm using this perl snipit on a Solaris 2.51 box running Perl 5.00403
my($s)=IO::Socket::INET->new(
PeerAddr => $host,
PeerPort => $port,
Proto =>'tcp',
Type => SOCK_STREAM,
Timeout => $to);
and any $to value has no affect on the Timeout. It remains constat @ ~4mins.
Any body know why and how I can fix it?
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V10 Issue 1302
***************************************
