You could have a circular reference in one of your objects. When the garbage collector comes along to deallocate this object, the circular reference means that everything referred to by that reference will never get freed. You can check for circular references with Devel::Cycle and Test::Memory::Cycle. One thing to try (although it might get expensive … Read more
One of the nice things about Perl is that it comes with a built in manual. Type in the following command: perldoc perlintro and take a look at the section Perl variable types. You can also see this on line with the perldoc.perl.org section on Perl variables. A quick overview: $foo is a scalar variable. … Read more
By default, STDOUT is line-buffered (flushed by LF) when connected to a terminal, and block-buffered (flushed when buffer becomes full) when connected to something other than a terminal. Furthermore, <STDIN> flushes STDOUT when it’s connected to a terminal. This means STDOUT isn’t connected to a terminal, you aren’t printing to STDOUT, or STDOUT’s been messed … Read more
Depending on what you want you will need to use ref or reftype (which is in Scalar::Util, a core module). If the reference is an object, ref will return the class of the object instead of the underlying reference type, reftype will always return the underlying reference type. if (ref $var eq ref {}) { … Read more
For most purposes, you probably won’t notice a difference. However, foreach reads each line into a list (not an array) before going through it line by line, whereas while reads one line at a time. As foreach will use more memory and require processing time upfront, it is generally recommended to use while to iterate … Read more
If you have root, type in console (Debian/Ubuntu): sudo apt-get install libdbi-perl
foreach my $key (keys %$ad_grp_ref) { … } Perl::Critic and daxim recommend the style foreach my $key (keys %{ $ad_grp_ref }) { … } out of concerns for readability and maintenance (so that you don’t need to think hard about what to change when you need to use %{ $ad_grp_obj[3]->get_ref() } instead of %{ $ad_grp_ref … Read more
A Python solution using BeautifulSoup4 (Edit: with proper skipping. Edit3: Using class=”details” to select the table): from bs4 import BeautifulSoup html = “”” <table class=”details” border=”0″ cellpadding=”5″ cellspacing=”2″ width=”95%”> <tr valign=”top”> <th>Tests</th> <th>Failures</th> <th>Success Rate</th> <th>Average Time</th> <th>Min Time</th> <th>Max Time</th> </tr> <tr valign=”top” class=”Failure”> <td>103</td> <td>24</td> <td>76.70%</td> <td>71 ms</td> <td>0 ms</td> <td>829 ms</td> </tr> … Read more
When you copy a hashref into another scalar, you are copying a reference to the same hash. This is similar to copying one pointer into another, but not changing any of the pointed-to memory. You can create a shallow copy of a hash easily: my $copy = { %$source }; The %$source bit in list … Read more
For literal (static) regexes there’s nothing to do — Perl will only compile them once. if ($var =~ /foo|bar/) { # … } For regexes stored in variables you have a couple of options. You can use the qr// operator to build a regex object: my $re = qr/foo|bar/; if ($var =~ $re) { # … Read more