Often, you only need to use a variable to store a single text or numeric value. Such variables are referred to as scalar variables in Perl.
Scalar Variable Names
Perl scalar variables are prefixed by the dollar sign ($) character. In addition, all Perl variable names must follow these rules:
- Variable names must contain only letters (a-z, A-Z), underscores (_), and numeric digits (0-9).
- The first character of a variable name must be a letter (a-z, A-Z) or underscore (_).
- Variable names are case-sensitive, so myvariable is not the same as MyVariable.
Some variable names are used by WebAssign. These variables are listed in the documentation.
$variable = value;
where variable is the variable name and value is the value to be assigned. The value can be either a single value or a Perl expression that results in a value.
Examples
The following example variable assignment statements should be inside an <EQN> or <eqn> tag.
# set $radius equal to 5
$radius = 5;
# calculate the $diameter
$diameter = $radius * 2;
# use the predefined variable $pi
$circumference = $diameter * $pi;
# use ** for exponentiation
$area = $pi * $radius ** 2;
# use quotes to enclose a text value
$message1 = 'The radius is ';
# concatenate strings as text with the period (.)
$message2 = $message1 . $radius;
# in double quotes, the value of a variable is substituted
$message3 = "The diameter is $diameter.";