sign()#

relationalai.std.math

#sign(x: Number | Producer) -> Expression

Calculates the sign of a number with the same type as x. The sign of a number is 1 if the number is positive, -1 if the number is negative, and 0 if the number is zero. Must be called in a rule or query context.

Parameters#

Name	Type	Description
`x`	`Number` or `Producer`	The number to take the sign of.

Returns#

An Expression object.

Example#

#import relationalai as rai
from relationalai.std import alias
from relationalai.std.math import sign

# Create a model with `Account` and `Transaction` types.
model = rai.Model("people")
Account = model.Type("Account")
Transaction = model.Type("Transaction")

# Add some people to the model.
with model.rule():
    account = Account.add(id="ACC1", balance=0.0)
    Transaction.add(id=1, account=account, amount=50.0)
    Transaction.add(id=2, account=account, amount=-25.0)

# What is the sign of each transaction amount?
with model.query() as select:
    t = Transaction()
    sign_amount = sign(t.amount)
    response = select(t.id, t.amount, alias(sign_amount, "sign_amount"))

print(response.results)
# Output:
#    id  amount  sign_amount
# 0   1    50.0          1.0
# 1   2   -25.0         -1.0