How can I create binary trees in Perl?
How do can I create binary trees in Perl? ...
perl
How to determine where a program stores data in a MySQL database
I have a commercial program that takes input from a delimited text file and stores that data in a MySQL database. I am writing a Perl script that essentially removes the need for the commercial program and uploads the data directly to the database. However, I am unsure in which tables the commercial program stores all the data. There ...
Is there a way to have a Windows shell script execute everything relative to its location rather than the location it was invoked from?
I'm aware of %~dp0, which represents the fully expanded directory that contains the batch script, but what I'm looking for is either: a method to invoke the batch script from Perl in such a manner that allows me to use the batch script without modification and have all directories in it be in relation to the batch script location a sin...
How can I extract columns from a fixed-width format in Perl?
I'm writing a Perl script to run through and grab various data elements such as: 1253592000 1253678400 86400 6183.000000 1253764800 86400 4486.000000 1253851200 36.000000 86400 10669.000000 1253937600 0.000000 86400 9126.000000 1...
How can I check if I can call host() on a URI object in Perl?
I'm iterating through a list of links on a page, creating a URI object for each. When the URI object is created, I don't know whether the URL has a scheme, so when I later call $uri->host(), I will sometimes get Can't locate object method "host" via package "URI::_generic" at -e line 1. because the URI object is of type URI::_generic,...
How do I start a new Perl module distribution?
I'm trying to set up a large-ish project, written in Perl. The IBM MakeMaker tutorial has been very helpful so far, but I don't understand how to link all the modules into the main program. In my project root, I have MANIFEST, Makefile.PL, README, a bin directory, and a lib directory. In my bin directory, I have my main script (Main.p...
How do I sort by value from a second level hash, in Perl?
my $hash_ref = { one => { val => 1, name => 'one' }, three => { val => 3, name => 'three'}, two => { val => 2, name => 'two' }, }; I would like to sort $hash_ref such that a foreach would order them by $hash_ref->{$key}->{'val'} one two three Any suggestions? ...
How do I install Perl script dependencies?
I have several scripts that I supply to users as tools for their engineering projects. These scripts contain a lot of duplicated code. I want to extract this code and maintain it in a set of modules. However, in order for this to work, the users would have to install these modules. I don't want to have to tell my users to "make install",...
How can I capture the output of pkgrm in Perl?
I want to uninstall a package in Solaris, say NewPackage. For that I am using the command: pkgrm NewPackage It will display all the steps in the STDOUT and at the end it will give the message that the package is uninstalled successfully. If i want to uninstall the same package in a Perl program how do I redirect the STDOUT messages ...
How can I detect which line I'm processing in Perl?
Got a text file that looks like: 200.0 250.0 300.0 350.0 400.0 162:02:10 017:01:56 017:08:18 011:16:22 008:40:18 580.0 600.0 620.0 640.0 660.0 004:04:01 001:47:27 007:25:29 017:44:53 003:07:34 Trying to parse out lines 1 & 3 as "values", and lines 2 & 4 as "times". My code: if($line =~ /^...
How do I create a table trigger with DBD::SQLite?
Can anyone provide syntax to create a table trigger preferably with DBI's do() method. It doesn't seem to like me putting everything on one line. Not sure what i'm doing wrong. Here's what I've got: $dbh->do("CREATE TABLE image(img_id integer primary key, md5sum text, path text, name text, date DATE)"); $dbh->do("CREATE TRIGGER insert_i...
Does Perl perform common subexpression elimination?
Hi, I wonder if Perl performs common subexpression elimination? And what kind of optimisations are done? ...
How can I FTP a file with an SSH key instead of a password, in Perl?
My local system and remote server is configured with ssh key exchange. and I want to get the XML files from the remote system with the NET::FTP packages. Can you suggest a way to do the file transfer with Net::FTP package, but without a password? ...
How do I insert a lot of whitespace in Perl?
I need to buff out a line of text with a varying but large number of whitespace. I can figure out a janky way of doing a loop and adding whitespace to $foo, then splicing that into the text, but it is not an elegant solution. ...
How can I override Perl's open() function but use the same filehandle for testing?
Hi, I am currently adding some unit tests to some legacy code and I find myself with the need to override an open function. The live code looks something like this. if ( !open( F, $filetoopen) ){ # do stuff with <F> } What I want to do is make sure that "F" contains a file handle that I have provided from my tests rather than wha...
How do I write a Perl constructor in XS?
I am trying to write new XS module for Perl. I have tested by following XS module writing instruction and it is working fine. I am not able to understand how to I write new method for XS I have a package called Agent. I want to be able to something like this: my $agent_object = new Agent; ...
"callback" from PayPal to confirm payment?
I have a very simple online ordering app in Perl. The user fills in a form, and when they submit, my app inserts the info into a mySql database, then redirects them to PayPal to complete the payment. The problem is that the database does not have any information about whether they actually completed the payment. I end up having to man...
Should a Perl constructor return an undef or a "invalid" object?
Question: What is considered to be "Best practice" - and why - of handling errors in a constructor?. "Best Practice" can be a quote from Schwartz, or 50% of CPAN modules use it, etc...; but I'm happy with well reasoned opinion from anyone even if it explains why the common best practice is not really the best approach. As far as my o...
How can I add a newline after X number of characters in Perl?
I was wondering how can I add a newline character (i.e. /n or <br>) after X number of characters. For example, let's say I have a perl variable $message ="aaaaabbbbbcccccdd". I want to add a newline character after every 5 characters to this variable. So when I print the variable in html it will display: aaaaa bbbbb ccccc dd What...
Listening a socket on client machine using Javascript
Is that possible? I'm writing a web-admin interface for a network-system. I need to listen to a specific UDP port and show it in browser. Can I do that in javascript? Also; any other ideas are welcomed. early-edit: Here's another idea: I have php and perl support at server-side. JS can call a php script to start listening, which will a...