programming-for-dummies

560
The Structure of a Perl/Python Program
Both Perl and Python are used in Web applications but also for more specialized
uses, such as text manipulation. Perl is particularly popular in the field
of bioinformatics and finance whereas Python has been adapted as a scripting
language for many graphics and animation programs.
Although system programming languages like C/C++ were designed to maximize
the efficiency of computer equipment, languages like Perl and Python
are designed to maximize the efficiency of programmers, who are now more
expensive than computer equipment. When programmers need to write
something in a hurry that doesn’t involve manipulating the hardware of a
computer, they often turn to Perl and Python.
Python is often associated with the British comedy troupe “Monty Python’s
Flying Circus.” It’s considered good form among Python programmers to slip
in Monty Python references in their programs whenever possible.
The Structure of a Perl/Python Program
Because Perl and Python are interpreted languages, you can often type in
commands a line at a time or type and save commands in a file. A simple Perl
program might look like this:
print “This is a simple Perl program.\n”;
exit;
A Python program is even simpler:
print “This is a simple Python program.”
Perl adapts the syntax of the C language including the use of semicolons at
the end of each statement and the use of curly brackets to identify a block of
commands. Python omits semicolons, and instead of using curly brackets to
identify a block of comments, Python uses indentation. To identify a block of
commands in Perl, use curly brackets like this:
if $x > 5
{
command1;
command2;
}
In Python, the same program might look like this:
if x > 5:
command1;
command2;