[21958] in Perl-Users-Digest
Perl-Users Digest, Issue: 4180 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Nov 26 11:11:22 2002
Date: Tue, 26 Nov 2002 08:10:14 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Tue, 26 Nov 2002 Volume: 10 Number: 4180
Today's topics:
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@augustmail.com
rounding numbers (RC)
Re: rounding numbers <nobody@dev.null>
Re: rounding numbers (Helgi Briem)
Re: rounding numbers <BROWNHIK@Syntegra.Bt.Co.Uk>
Re: rounding numbers <nobody@dev.null>
split() vs. m// in list context (was Re: matching a pat (Tad McClellan)
splitting with positive look-behind <jvandervloet@hotmail.com>
Re: the system command and parameters (Windows). (Tad McClellan)
Two pppd's one after the other... <vic50x@email.it>
Variable / array problem <jon@rogers.tv>
Re: Variable / array problem <perl-dvd@ldschat.com>
Re: Variable / array problem (Tad McClellan)
Re: Variable / array problem <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Tue, 26 Nov 2002 08:46:01 -0600
From: tadmc@augustmail.com
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.2 $)
Message-Id: <vb6cnbocuOe0FH6gXTWc2Q@august.net>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.2 $)
This newsgroup, commonly called clpmisc, is a technical newsgroup
intended to be used for discussion of Perl related issues (except job
postings), whether it be comments or questions.
As you would expect, clpmisc discussions are usually very technical in
nature and there are conventions for conduct in technical newsgroups
going somewhat beyond those in non-technical newsgroups.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://mail.augustmail.com/~tadmc/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Please do not use the existence of these guidelines as a
"license to flame" or other meanness. It is possible that
a poster is not aware of the things discussed here. Let's
give them the benefit of the doubt, and just help them learn
how to post, rather than assume that they do know and are
being the "bad kind" of Lazy.
A note about technical terms used here:
In this document, we use words like "must" and "should" in the
very precise sense that they're used in technical conversation
(such as you're likely to encounter in this newsgroup). When
we say that you *must* do something, we mean that if you don't
do that something, then it's very unlikely that you're going to
get much benefit from using this group. We're not trying to boss
you around; we're just trying to convey the point without using
a lot of words.
Do *NOT* send email to the maintainer of these guidelines. It will be
discarded unread. The guidelines belong to the newsgroup so all
discussion should appear in the newsgroup. I am just the secretary that
writes down the consensus of the group.
Before posting to comp.lang.perl.misc
Must
This section describes things that you *must* do before posting to
clpmisc, in order to maximize your chances of getting meaningful replies
to your inquiry and to avoid getting flamed for being lazy and trying to
have others do your work.
The perl distribution includes documentation that is copied to your hard
drive when you install perl. Also installed is a program for looking
things up in that (and other) documentation named 'perldoc'.
You should either find out where the docs got installed on your system,
or use perldoc to find them for you. Type "perldoc perldoc" to learn how
to use perldoc itself. Type "perldoc perl" to start reading Perl's
standard documentation.
Check the Perl Frequently Asked Questions (FAQ)
Checking the FAQ before posting is required in Big 8 newsgroups in
general, there is nothing clpmisc-specific about this requirement.
You are expected to do this in nearly all newsgroups.
You can use the "-q" switch with perldoc to do a word search of the
questions in the Perl FAQs.
Check the other standard Perl docs (*.pod)
The perl distribution comes with much more documentation than is
available for most other newsgroups, so in clpmisc you should also
see if you can find an answer in the other (non-FAQ) standard docs
before posting.
It is *not* required, or even expected, that you actually *read* all of
Perl's standard docs, only that you spend a few minutes searching them
before posting.
Try doing a word-search in the standard docs for some words/phrases
taken from your problem statement or from your very carefully worded
"Subject:" header.
Really Really Should
This section describes things that you *really should* do before posting
to clpmisc.
Lurk for a while before posting
This is very important and is expected regardless of what newsgroup
you are visiting. Lurking means to simply monitor a newsgroup for a
period of time until you become very familiar with local customs.
Think of a newsgroup as foreign culture. Each newsgroup has its own
specific customs and rituals. Get to know those customs and rituals
well before you participate. This will help you to avoid
embarrassing social situations. Consider yourself to be a foreigner
at first!
Search a Usenet archive
There are tens of thousands of Perl programmers. It is very likely
that your question has already been asked (and answered). See if you
can find where it has already been answered.
One such searchable archive is:
http://groups.google.com/advanced_group_search
If You Like
This section describes things that you *can* do before posting to
clpmisc.
Check Other Resources
You may want to check in books or on web sites to see if you can
find the answer to your question.
But you need to consider the source of such information: there are a
lot of very poor Perl books and web sites, and several good ones
too, of course.
Posting to comp.lang.perl.misc
There can be 200 messages in clpmisc in a single day. Nobody is going to
read every article. They must decide somehow which articles they are
going to read, and which they will skip.
Your post is in competition with 199 other posts. You need to "win"
before a person who can help you will even read your question.
These sections describe how you can help keep your article from being
one of the "skipped" ones.
Is there a better place to ask your question?
Question should be about Perl, not about the application area
It can be difficult to separate out where your problem really is,
but you should make a conscious effort to post to the most
applicable newsgroup. That is, after all, where you are the most
likely to find the people who know how to answer your question.
Being able to "partition" a problem is an essential skill for
effectively troubleshooting programming problems. If you don't get
that right, you end up looking for answers in the wrong places.
It should be understood that you may not know that the root of your
problem is not Perl-related (the two most frequent ones are CGI and
Operating System related), so off-topic postings will happen from
time to time. Be gracious when someone helps you find a better place
to ask your question by pointing you to a more applicable newsgroup.
How to participate (post) in the clpmisc community
Carefully choose the contents of your Subject header
You have 40 precious characters of Subject to win out and be one of
the posts that gets read. Don't waste them. Take care while
composing them, they are the key that opens the door to getting an
answer.
Spend them indicating what aspect of Perl others will find if they
should decide to read your article.
Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.perl.com/CPAN-local/authors/Dean_Roehrich/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* the sections of quoted text
that your comments apply to. Failure to do this is called "Jeopardy"
posting because the answer comes before the question.
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://www.geocities.com/nnqweb/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan <tadmc@augustmail.com> and many others on the
comp.lang.perl.misc newsgroup.
------------------------------
Date: 26 Nov 2002 06:31:00 -0800
From: smuston@iprimus.com.au (RC)
Subject: rounding numbers
Message-Id: <98814e67.0211260631.43c148ec@posting.google.com>
does anyone know how to round numbers with lots of decimal places to a
certain amount. eg 2 decimal places or 0 decimal places
------------------------------
Date: Tue, 26 Nov 2002 14:50:47 GMT
From: Andras Malatinszky <nobody@dev.null>
Subject: Re: rounding numbers
Message-Id: <3DE389F8.5070805@dev.null>
RC wrote:
> does anyone know how to round numbers with lots of decimal places to a
> certain amount. eg 2 decimal places or 0 decimal places
Use the printf() function. I'd explain how, but it is so much more
eloquently done in the perlfaq4 manpage. (You probably missed it when
you typed
perldoc -q round
to check the FAQ, didn't you?)
------------------------------
Date: Tue, 26 Nov 2002 15:07:25 GMT
From: helgi@decode.is (Helgi Briem)
Subject: Re: rounding numbers
Message-Id: <3de38d7d.3585403046@news.cis.dfn.de>
On 26 Nov 2002 06:31:00 -0800, smuston@iprimus.com.au (RC)
wrote:
>does anyone know how to round numbers with lots of decimal places to a
>certain amount. eg 2 decimal places or 0 decimal places
This is a Frequently Asked Question. Answers to FAQs
are to be found in the standard Perl documentation that
is bundled with every Perl distribution. The documentation
can be searched and browsed using the perldoc program
that is also bundled (see "perldoc perldoc" for details).
As for your question, use sprintf:
my $pi = sprintf("%.2f", 3.1415926535);
See "perldoc -q round" and "perldoc -f sprintf" for further
details.
--
Regards, Helgi Briem
helgi AT decode DOT is
A: Top posting
Q: What is the most irritating thing on Usenet?
- "Gordon" on apihna
------------------------------
Date: Tue, 26 Nov 2002 15:35:20 -0000
From: "Kevin Brownhill" <BROWNHIK@Syntegra.Bt.Co.Uk>
Subject: Re: rounding numbers
Message-Id: <as04np$p47$1@pheidippides.axion.bt.co.uk>
"Andras Malatinszky" <nobody@dev.null> wrote in message
news:3DE389F8.5070805@dev.null...
>
>
> RC wrote:
>
> > does anyone know how to round numbers with lots of decimal places to a
> > certain amount. eg 2 decimal places or 0 decimal places
>
>
>
> Use the printf() function. I'd explain how, but it is so much more
> eloquently done in the perlfaq4 manpage. (You probably missed it when
> you typed
>
> perldoc -q round
>
> to check the FAQ, didn't you?)
>
>
Surely printf() just prints the number in a certain format.
To round the number to 2 places, use the following:
$rounded = int($number * 100 + 0.5) / 100;
for 4 places, change the 100s to 10000s
------------------------------
Date: Tue, 26 Nov 2002 15:58:50 GMT
From: Andras Malatinszky <nobody@dev.null>
Subject: Re: rounding numbers
Message-Id: <3DE399EB.3070408@dev.null>
Kevin Brownhill wrote:
> "Andras Malatinszky" <nobody@dev.null> wrote in message
> news:3DE389F8.5070805@dev.null...
>
>>
>>RC wrote:
>>
>>
>>>does anyone know how to round numbers with lots of decimal places to a
>>>certain amount. eg 2 decimal places or 0 decimal places
>>>
>>
>>
>>Use the printf() function. I'd explain how, but it is so much more
>>eloquently done in the perlfaq4 manpage. (You probably missed it when
>>you typed
>>
>>perldoc -q round
>>
>>to check the FAQ, didn't you?)
>>
>>
>>
>
> Surely printf() just prints the number in a certain format.
>
> To round the number to 2 places, use the following:
> $rounded = int($number * 100 + 0.5) / 100;
I don't know about that, Kevin:
for $number (42.213, 42.21, 42.2, 42, -17.231, -17.23, -17.2, -17) {
my $rounded = int($number * 100 + 0.5) / 100;
print "$number rounded to two decimals is $rounded\n";
};
42.213 rounded to two decimals is 42.21
42.21 rounded to two decimals is 42.21
42.2 rounded to two decimals is 42.2
42 rounded to two decimals is 42
-17.231 rounded to two decimals is -17.22
-17.23 rounded to two decimals is -17.22
-17.2 rounded to two decimals is -17.19
-17 rounded to two decimals is -16.99
You are doing well with the first two numbers, the next two answers are
kinda borderline, then it's all downhill from there.
I think you are better off with printf(), and if you want to do more
than printing, you can always use sprintf():
for $number (42.213, 42.21, 42.2, 42, -17.231, -17.23, -17.2, -17) {
my $rounded = sprintf("%.2f", $number);
print "$number rounded to two decimals is $rounded\n";
};
42.213 rounded to two decimals is 42.21
42.21 rounded to two decimals is 42.21
42.2 rounded to two decimals is 42.20
42 rounded to two decimals is 42.00
-17.231 rounded to two decimals is -17.23
-17.23 rounded to two decimals is -17.23
-17.2 rounded to two decimals is -17.20
-17 rounded to two decimals is -17.00
------------------------------
Date: Tue, 26 Nov 2002 07:48:16 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: split() vs. m// in list context (was Re: matching a pattern from a text file into a Hash.)
Message-Id: <slrnau6ut0.35i.tadmc@magna.augustmail.com>
Dominik Seelow <kurzhalsflasche@netscape.net> wrote:
> Apparently you're not sure whether to use a regular expression or to
> split - and try do both.
Use split() if you want to specify what to "throw away".
use m// (or m//g) in a list context if you want to specify what to "keep".
They are (kinda) opposites.
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Tue, 26 Nov 2002 15:39:38 GMT
From: "joeri" <jvandervloet@hotmail.com>
Subject: splitting with positive look-behind
Message-Id: <_AME9.21157$Ti2.4191@afrodite.telenet-ops.be>
Hi,
I'm trying to split the following piece of text into sentences:
$text = "HISTORY OF PRESENT ILLNESS: Mr. x, M.D. is an 83-year-old man with
past medical history inc. hypertension, congestive heart failure. Atrial
fibrillation, hypercholesterolemia, history of CVA who presented to Stanford
Emergency Room on April 25 with chief complaint of right-sided chest pain
since April 24.";
I only want to split on sentence boundaries like \., \? and \!. But I don't
want to split when an abbreviation is encountered. Also, I need to keep the
sentence boundary symbol. So I came up with the following:
@sents = split(/(?<=[^Mr|Ms|M\.D|inc][.?!])\s+/, $text);
This works fine and gives me:
HISTORY OF PRESENT ILLNESS: Mr. Pedersen, M.D. is an 83-year-old man with
past medical history inc. hypertension, congestive heart failure.
Atrial fibrillation, hypercholesterolemia, history of CVA who presented to
Stanford Emergency Room on April 25 with chief complaint of right-sided
chest pain since April 24.
But if I add the abbreviation 'e.g.' to the RE like so:
@sents = split(/(?<=[^Mr|Ms|M\.D|inc|e\.g][.?!])\s+/, $text);
The piece of text is not split anywhere.
I have looked through the previous posts, but I couldn't find a suitable
answer.
Can anyone tell me what I'm doing wrong here?
Thanks,
J.
------------------------------
Date: Tue, 26 Nov 2002 09:14:00 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: the system command and parameters (Windows).
Message-Id: <slrnau73to.38b.tadmc@magna.augustmail.com>
Sascha Kerschhofer <skerschhofer@yahoo.de> wrote:
> I have the problem, that, the system command seems to behave different on
> diverse windows installations (but it is all Windows 2000 - one english and
> one german version):
> to want to execute
> msxsl.exe file1.xml file1.xsl -xw > file1.htm filename=000001
> and I call
> system("msxsl.exe $file.h.xml file1.xsl -xw >
> $file.htm","filename=$the_filename");
>
> on my system, it performs well, on other system, the second element of the
> LIST
Reread the first paragraph of
perldoc -f system
and take note of what system() does when LIST contains more
than one element.
> (which is 'filename=$the_filename') causes an error as "The system
> cannot find the path specified."
> If I remove the second element of the LIST, it runs as it should. What am I
> doing wrong, or has windows commandshell it's secrets?
The commandshell is not involved, since you've used more than
one element in system's list.
Since you appear to want to do redirection of the output, you
_want_ a commandshell to be involved, so call system() with
a single-element list:
system(
"msxsl.exe $file.h.xml file1.xsl -xw > $file.htm filename=$the_filename");
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Tue, 26 Nov 2002 16:07:52 +0000
From: Vittorio <vic50x@email.it>
Subject: Two pppd's one after the other...
Message-Id: <3DE39C58.5010009@email.it>
To connect my linux laptop to my office network via modem and a win nt
RAS CALLBACK server, I manually run two pppd processes one at the end of
the other by means of:
pppd call firstcall
pppd call secondwait
where firstcall calls the win nt server giving it the phone number to be
called back; as soon as firstcall exit I manually run secondwait which
starts waiting for the incoming call from the NT RAS server.
Could you please help me to setup a perl procedure to make the same
automagically?
I know that, if firstcall finishes ok then a completion code 14 is
emitted by pppd.......
Ciao
Vittorio
------------------------------
Date: Tue, 26 Nov 2002 16:09:12 +0100
From: Jon Rogers <jon@rogers.tv>
Subject: Variable / array problem
Message-Id: <3DE38E8F.70D2195E@rogers.tv>
Hello
I'd like to make sure a variable isn't longer than 10 bytes:
if (length $var > 10) {
while (length $var > 10) {
REMOVE_ONE_BYTE_FROM_RIGHT
}
}
How could I do this?
And if I have an array @arr = (a,b,c,d,e);
how would I remove position two, shifting the elements that are to the
right of position two one step to the left?
Hope anyone knows,
Jon
------------------------------
Date: Tue, 26 Nov 2002 08:08:23 -0700
From: "David" <perl-dvd@ldschat.com>
Subject: Re: Variable / array problem
Message-Id: <G0ME9.7569$EY.272@fe01>
"Jon Rogers" <jon@rogers.tv> wrote in message
news:3DE38E8F.70D2195E@rogers.tv...
> Hello
>
> I'd like to make sure a variable isn't longer than 10 bytes:
>
> if (length $var > 10) {
> while (length $var > 10) {
> REMOVE_ONE_BYTE_FROM_RIGHT
> }
> }
>
> How could I do this?
Personaly, I would do something to the effect of this:
# substr( Variable, starting point, length to keep)
$var = substr($var, 0, 10) if (length($var) > 10);
> And if I have an array @arr = (a,b,c,d,e);
>
> how would I remove position two, shifting the elements that are to the
> right of position two one step to the left?
You can use splice like this:
# splice( Array, SkipElements, ReplaceHowManyElements,
ListOfElementsToPutInThisPlace)
splice(@arr, 1, 1);
# so we are saying skip the first element, then replace the one element
with nothing
Regards,
David
------------------------------
Date: Tue, 26 Nov 2002 09:34:18 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: Variable / array problem
Message-Id: <slrnau753q.3jr.tadmc@magna.augustmail.com>
Jon Rogers <jon@rogers.tv> wrote:
> I'd like to make sure a variable isn't longer than 10 bytes:
> How could I do this?
$var = substr $var, 0, 10;
or
substr($var, 10) = '';
> And if I have an array @arr = (a,b,c,d,e);
^^^^^^^^^
^^^^^^^^^ barewords are Bad
> how would I remove position two, shifting the elements that are to the
> right of position two one step to the left?
splice @arr, 1, 1;
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Tue, 26 Nov 2002 16:36:31 +0100
From: Koos Pol <koos_pol@NO.nl.JUNK.compuware.MAIL.com>
Subject: Re: Variable / array problem
Message-Id: <newscache$vow66h$gma$1@news.emea.compuware.com>
Jon Rogers wrote (Tuesday 26 November 2002 16:09):
> Hello
>
> I'd like to make sure a variable isn't longer than 10 bytes:
Are you sure you want to do this? You will ruin your data if you
don't account for 16/32/64/128/... bits architectures!
> if (length $var > 10) {
> while (length $var > 10) {
> REMOVE_ONE_BYTE_FROM_RIGHT
> }
> }
>
> How could I do this?
I suspect you want to check for the amount of characters. That is,
the length of the string (scalar). In that case you will probably
want to use substr().
> And if I have an array @arr = (a,b,c,d,e);
>
> how would I remove position two, shifting the elements that are to the
> right of position two one step to the left?
read "perldoc splice"
>
> Hope anyone knows,
>
> Jon
HTH
--
KP
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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