String()#

relationalai.std.strings

#String(item: Any) -> Expression

Checks if an item is a string. Must be called in a rule or query context.

Parameters#

Name	Type	Description
`item`	`Any`	The item to check.

Returns#

An Expression object.

Example#

#import relationalai as rai
from relationalai.std.strings import String

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

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

# Add some people to the model.
with model.rule():
    Person.add(id=1).set(name="Alice")
    Person.add(id="2").set(name="Bob")  # Note that the id is a string.

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

with model.query() as select:
    person = Person()
    String(person.id)  # Filter people whose id is a string.
    response = select(person.name)

print(response.results)
#   name
# 0  Bob

with model.query() as select:
    person = Person()
    with model.not_found():
        String(person.id)  # Filter people whose id is not a string.
    response = select(person.name)

print(response.results)
#     name
# 0  Alice