log()#

relationalai.std.math

#log(x: Number | Producer, base: Number | Producer | None = None) -> Expression

Calculates the logarithm of a number. If base is None, the natural logarithm is used (base e). Must be called in a rule or query context.

Parameters#

Name	Type	Description
`x`	`Number` or `Producer`	The number to take the logarithm of.
`base`	`Number` or `Producer` or `None`	The base of the logarithm. If `None`, the natural logarithm is used (base e).

Returns#

An Expression object.

Example#

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

# Create a model with a `Person` type.
model = rai.Model("people")
Person = model.Type("Person")

# Add some people to the model.
with model.rule():
    Person.add(name="Alice", age=9)
    Person.add(name="Bob", age=16)
    Person.add(name="Charlie", age=25)

# What is the log base 2 of each person's age?
with model.query() as select:
    p = Person()
    age_log2 = log(p.age, base=2)
    response = select(p.name, alias(age_log2, "age_log2"))

print(response.results)
# Output:
#       name  age_log2
# 0    Alice  3.169925
# 1      Bob  4.000000
# 2  Charlie  4.643856