Intermediate Perl

6.1. Using the Debugger to View Complex Data The Perl debugger can display complex data easily. For example, let's single-step through one version of the byte-counting program from Chapter 5: my %total_bytes; while (<&g...

6.2. Viewing Complex Data with Data::Dumper Another way to visualize a complex data structure rapidly is to dump it. A particularly nice dumping package is included in the Perl core distribution, called Data::Dumper. Let's replace the las...

6.3. YAML Data::Dumper is not the only game on the island, though. Brian Ingerson came up with Yet Another Markup Language (YAML) to provide a more readable (and more compact) dump. It works in the same way as Data::Dumper. We'll see m...

6.4. Storing Complex Data with Storable We can take the output of Data::Dumper's Dumper routine, place it into a file, and then load the file to a different program. When we evaluate the code as Perl code, we end up with two package varia...

6.5. Using the map and grep Operators As the data structures become more complex, it helps to have higher-level constructs deal with common tasks such as selection and transformation. In this regard, Perl's grep and map operators are worth mast...

6.6. Applying a Bit of Indirection Some problems that may appear very complex are actually simple once we've seen a solution or two. For example, suppose we want to find the items in a list that have odd digit sums but don't want the item...

6.7. Selecting and Altering Complex Data We can use these operators on more complex data. Taking the provisions list from Chapter 5: my %provisions = ( 'The Skipper' => [qw(blue_shirt hat jacket preserver sunscreen)], ...

6.8. Exercises You can find the answers to these exercises in "Answers for Chapter 6" in the Appendix. 6.8.1. Exercise 1 [20 min] The program from Exercise 2 in Chapter 5 needs to read the entire datafile each time it runs. However, the Profes...