As seen in Expression variables
and also in the Complete variable examples,
variables are not mysterious. They can be
iterative or non-iterative and their operation
can be spelled out. On the other hand, the
pre-defined variables for doing simple statistics
may be limiting. Maybe we need an iteratively
calculated value that uses a different type than
numeric. This is where
custom variables may be
useful.
For a custom variable, all
details can be freely defined:
the base type: numeric,
string or
datetime;
number is also
accepted as an alias for
numeric
the base expression
two intermediary expressions that both may use the base expression's result, and the second intermediary may also use the first one's result
the result expression that may use all three expressions' results
See the Custom variable example on how the
average type variable
can be spelled out as a custom variable.