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relationalai.std.strings.replace()

replace(string: str|Producer, old: str|Producer, new: str|Producer) -> Expression

Replaces all occurrences of a substring in a string. If any of the arguments are Producer objects, replace() 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`	`str` or `Producer`	A string or a producer that produces string values.
`old`	`str` or `Producer`	The substring to replace.
`new`	`str` or `Producer`	The substring to replace `old` with.

Returns

An Expression object.

Example

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 new_name property equal to the name property with all occurrences of
# "ice" replaced with "icia".
with model.rule():
    person = Person()
    person.set(new_name=strings.replace(person.name, "ice", "icia"))

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

print(response.results)
#    id   name new_name
# 0   1  Alice   Alicia
# 1   2    Bob      Bob
# 2   3     -1      NaN

See Also