Expression#
relationalai
#class Expression
Expression
is a subclass of Producer
that produces the results of
aggregations and mathematical operations involving Producer
objects.
Must be used in a rule or query context.
Example#
You create an Expression
object when you use an operator like >
with a Producer
object:
#import relationalai as rai
model = rai.Model("people")
Person = model.Type("Person")
with model.rule():
Person.add(name="Fred", age=39)
Person.add(name="Wilma", age=36)
with model.query() as select:
person = Person()
# Restrict `person.age` to values strictly greater than 36
# and return an `Expression` object.
person.age > 36
response = select(person.name)
print(response.results)
# Output:
# name
# 0 Fred
The following operators are supported:
- Add (
+
) - Subtract (
-
) - Multiply (
*
) - Power (
**
) - Divide (
/
) - Floor divide (
//
) - Modulo (
%
) - Equal (
==
) - Not equal (
!=
) - Greater than (
>
) - Greater than or equal (
>=
) - Less than (
<
) - Less than or equal (
<=
)