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==== Arrays ====
==== Arrays ====
An array represents a list of values:
my @animals = ("camel", "llama", "owl");
my @animals = ("camel", "llama", "owl");
my @mixed = ("camel", 42, 1.23);
my @mixed = ("camel", 42, 1.23);
Arrays are zero-indexed. Here's how you get at elements in an array:
print $animals[0]; # prints "camel"
print $animals[0]; # prints "camel"
print $animals[1]; # prints "llama"
print $animals[1]; # prints "llama"
The special variable '''$#array''' tells you the index of the last element of an array:
print $mixed[$#mixed]; # last element, prints 1.23
print $mixed[$#mixed]; # last element, prints 1.23
You might be tempted to use '''$#array + 1''' to tell you how many items there are in an array. Don't bother. As it happens, using '''@array''' where Perl expects to find a scalar value ("in scalar context") will give you the number of elements in the array:
if (@animals < 5) { ... }
if (@animals < 5) { ... }
The elements we're getting from the array start with a '''$''' because we're getting just a single value out of the array; you ask for a scalar, you get a scalar.
To get multiple values from an array:
@animals[0,1]; # gives ("camel", "llama");
@animals[0,1]; # gives ("camel", "llama");
@animals[1..$#animals]; # gives all except the first element
@animals[1..$#animals]; # gives all except the first element
This is called an "array slice".
You can do various useful things to lists:
my @sorted = sort @animals;
my @sorted = sort @animals;
my @backwards = reverse @numbers;
my @backwards = reverse @numbers;
There are a couple of special arrays too, such as '''@ARGV''' (the command line arguments to your script) and '''@_''' (the arguments passed to a subroutine). These are documented in [http://perldoc.perl.org/perlvar.html perlvar].
==== Hashes ====
==== Hashes ====
