relationalai.std.strings.lowercase()

lowercase(string: str|Producer) -> Expression

Converts a string to lowercase. If string is a Producer, then lowercase() acts as a filter and removes non-string values from the producer. Must be called in a rule or query context.

Parameters

Name	Type	Description
string	Producer or Python str object	The string to convert to lowercase.

Returns

An Expression object.

Example

Use lowercase() to convert a string to lowercase:

import relationalai as rai
from relationalai.std import strings


# =====
# SETUP
# =====

model = rai.Model("MyModel")
Person = model.Type("Person")

with model.rule():
    Person.add(id=1).set(name="Alice")
    Person.add(id=2).set(name="Bob")
    Person.add(id=3).set(name=-1)  # Non-string name


# =======
# EXAMPLE
# =======

# Set a lowercase_name property equal to the name property converted to lowercase.
with model.rule():
    person = Person()
    person.set(lowercase_name=strings.lowercase(person.name))

# Since lowercase() filters out non-string values, the lowercase_name property
# is not set for the person with id=3.
with model.query() as select:
    person = Person()
    response = select(person.id, person.lowercase_name)

print(response.results)
#    id lowercase_name
# 0   1          alice
# 1   2            bob
# 2   3            NaN

See Also

• uppercase()