The items attribute defines the pool of items to be selected by a list element.
<list>
or
/ items = [expression; expression; expression;...]item | Any value string, number, property, or numeric range to be included in the selection pool. |
expression | Any valid expression to be included in the selection pool. |
The item pool can consist of any valid expression, including numbers, strings, properties, and numeric ranges.
When specifying complex expressions such as equations or function calls, the list of expressions must be enclosed in square brackets '[]' and separated by semicolons ';'.
For simple items such as numbers, strings, properties and numeric ranges, items can be enclosed in parentheses and separated by spaces or commas. Note, when specifying a numeric range (e.g., 1-100), the characters within the range must NOT be separated by spaces.
The following randomly selects the name of a president:
<list presidents>
/ selectionmode = uniform
/ items = ("George Washington", "John Adams", "Thomas Jefferson")
</list>
The following selects a countdown of numbers:
<list countdown>
/ selectionmode = sequence
/ items = (3 2 1)
</list>
The following selects a value of 2 for odd numbered trials and 1 for even numbered trials:
<list evenodd>
/ selectionmode = sequence
/ items = [if ( floor(mod(block.test.currenttrialnumber, 2)) == 0 ) 1 else 2]
</list>
The following randoly selects from two ranges of numbers without replacement:
<list countdown>
/ items = (1-10, 20-21)
</list>