Rob,
Thanks for your suggestion. It worked!!
# script.pl
8252c
8252c
8252d
8252d
82534
82535
82535
82534
8253c
8253c
8253f
8253f
82542
82543
<- big long list ->
So this is what did the trick:
while (<DATA>) {
next unless /RequestId \[([[:xdigit:]]+)\]/;
print "$1\n";
}
Can you explain why this works but my orginal effort did not?
Many thanks,
Bill Harpley
-----Original Message-----
From: Rob Dixon [mailto:rob.di...@gmx.com]
Sent: Monday, January 26, 2009 7:19 PM
To: Perl Beginners
Cc: Bill Harpley
Subject: Re: Simple regex problem has me baffled
Bill Harpley wrote:
> Hello,
>
> I have simple regex problem that is driving me crazy.
>
> I am writing a script to analyse a log file. It contains Java related
> information about requests and responses.
>
> Each pair of Request (REQ) and Response (RES) calls have a unique
> Request ID. This is a 5 digit hex number contained in square brackets
> (e.g. "[81c2d]" ).
>
> Using timestamps in each log entry, I need to calculate the time
> difference between the start of the Request and the end of the
Response.
>
> As a first step, I thought I would identify the matching REQ/RES pairs
> in the log and then set about extracting the timestamp information and
> doing the calculations.
>
> I started with a simple script to extract the Request IDs from each
> log entry. Here is what one looks like (names have been changed to
> protect the innocent).
>
>
> [2009-01-23 09:20:48,719]TRACE [server-1] [http-80-5]
> a...@mydomain.net
> :090123-092048567:f5825 (SetCallForwardStatusImpl.java:call:54) -
> RequestId [81e80] SetCallForwardStatus.REQ { accountNumber:=W12345,
> phoneNumber:=12121212121, onBusyStatus:=true, busyCurrent:=voicemail,
> onNoAnswerStatus:=false, noAnswerCurent:=voicemail,
> onUncondStatus:=false, uncondCurrent:=voicemail }
>
> So I need to extract the 5 hex digits in "RequestId [81e80]". Sounds
> simple, eh?
>
> Here is a fragment of my initial script:
>
> open ( DATA, "< $INBOX/sample.log") || die "Cannot open source file:
> $!";
> open ( FILE, "> $INBOX/request.dat") || die "Cannot open request file:
> $!";
>
> chomp(@list=<DATA>);
>
> foreach $entry(@list)
> {
>
> $entry =~ /\[([a-z0-9]{5})\]/;
>
> print "$1\n"; # print to screen
>
> # print FILE "$1\n"; # print to file
> }
>
> I have spent quite a bit of time refining this expression and it looks
> OK to me. I basically just need to extract the 5-digit hex string and
> then write it to a file (or to screen).
>
> This is what I get when I run the script:
>
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 8252c
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 8252c
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 8252d
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 8252d
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 82534
> 82534
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 82535
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 82534
> 82534
> 82534
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044.
>
> 8253c
> 8253c
> 8253c
> Use of uninitialized value in concatenation (.) or string at
> ./magic.pl line 16, <DATA> line 1044
>
>
> < --- Big long list --note that RequestIDs from REQ/RES pairs need not
> be adjacent in the list -- >
>
> The first thing that puzzles me is that it obviously extracting the
> RequestId substring correctly, it seems to complain about the "$1\n"
> expression in line 16.
> This looks quite OK to me and I am baffled why I am getting this
> message.
>
> The other thing that puzzles me is that there can only be a single
> REQ/RES pair in the file with a given ID. So the RequestID should not
> appear more than twice in the The output list. Yet there are many
> instances where the RequestID appears more than twice.
>
> Any help you guys can provide would be much appreciated. The Perl
> version is 5.8.4. on solaris 10
I think I would write
while (<DATA>) {
next unless /RequestId \[([[:xdigit:]]+)\]/;
print "$1\n";
}
HTH,
Rob
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