Cross Ref > Data Structures

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Associative arrays are also known as a dictionary or a hash table in other languages.

Perl:   % Array Preface Syntax Example: my %weekdays = ( 'Sun' => 'Sunday', 'Mon' => 'Monday', 'Tue' => 'Tuesday', 'Wed' => 'Wednesday', 'Thu' => 'Thursday', 'Fri' => 'Friday', 'Sat' => 'Saturday', ); my $day_of_the_week = $weekdays{'Mon'};  Perl Associative Array (% Array Preface)	PHP:  Declare associative array with initial known values. You can also add to associative array. (You can just assign values without ever declaring it too!) Syntax Example: $prices = array( 'Tires'=>100, 'Spark Plugs'=>4 ); $prices['Oil'] = 10; echo "Tires=" . $prices['Tires'] . "<br>"; echo "Oil=" . $prices['Oil'] . "<br>";  PHP Associative Array

General Info: Pointers / References

A pointer is a variable type that allows you to refer indirectly to another object. Instead of holding data, a pointer holds the address to data -- the address of another variable or object. You can change the address value a pointer points to thus changing the variable or object the pointer is pointing to.

A reference is a type of pointer that cannot change and it must always point to a valid storage (no nulls).

Perl:  Perl supports both pointers and references.	PHP:   Not Supported PHP supports references which allow you to refer to the value of a variable but PHP does not support true developer defined pointers. You cannot get and use the address of a variable. However, you can still do inexpensive assignments by assigning by reference.