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relationalai.std.strings.starts_with()

starts_with(string: Producer, prefix: str|Producer) -> Expression

Filters values produced by a Producer to only include strings that begin with a specified prefix. Must be called in a rule or query context.

Parameters

Name	Type	Description
`string`	`Producer`	The string to check.
`prefix`	`str` or `Producer`	The prefix to check for.

Returns

An Expression object.

Example

Use starts_with() to filter strings that start with a specified prefix:

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")


# ========
# EXAMPLES
# ========

# Get all people whose name starts with "A".
with model.query() as select:
    person = Person()
    strings.starts_with(person.name, "A")
    response = select(person.id, person.name)

print(response.results)
#    id   name
# 0   1  Alice


# Get all people whose name does not start with "A".
with model.query() as select:
    person = Person()
    with model.not_found():
        strings.starts_with(person.name, "A")
    response = select(person.id, person.name)

print(response.results)
#    id name
# 0   2  Bob

See Also