Perl: Difference between revisions
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use English; | use English; | ||
== Arrays and lists == | |||
* Although used interchangeably, technically a list is the collection of elements whereas an array is the variable that points to the list. | |||
* <code>$#array</code> contains the last element index of the array. Since arrays are zero-indexed, the size of the array is <code>$#array + 1</code>. | |||
* Negative array indices start from the end of the list, so the last element can be accessed as <code>$array[-1]</code>. |
Revision as of 15:26, 5 September 2019
Robust scripts
All scripts should start with the following:
use strict; use warnings; use utf8; use autodie;
Only remove one or more of the above if you really know what you are doing.
It is also a good idea to define a minimum Perl version, e.g. to require Perl 5.14 or above:
use v5.14;
More readable names for common variables (e.g. $/
can be referred to as $INPUT_RECORD_SEPARATOR
) can be created with:
use English;
Arrays and lists
- Although used interchangeably, technically a list is the collection of elements whereas an array is the variable that points to the list.
$#array
contains the last element index of the array. Since arrays are zero-indexed, the size of the array is$#array + 1
.- Negative array indices start from the end of the list, so the last element can be accessed as
$array[-1]
.