relationalai.std.re.sub()

sub(
    regex: str|Producer,
    repl: string|Producer,
    string: str|Producer
) -> Expression

Replace all occurrences of regex is string with repl. If regex, repl, or string is a Producer, then sub() filters out non-string values from regex and repl and non-matching strings from string. Must be used in a rule or query context.

Tip

When passing a string literal, use a raw string — which is prefaced with an r, as in r"J.*" — to avoid escaping special characters in regular expressions.

Parameters

Name	Type	Description
regex	Producer or Python str	A regular expression string.
repl	Producer or Python str	The string to replace the matches with.
string	Producer or Python str	The string to match against.

Returns

An Expression object.

Example

Use the sub() function to replace all occurrences of a regular expression in a string:

import relationalai as rai
from relationalai.std import re


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

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

with model.rule():
    Person.add(id=1).set(full_name="Alan Turing")
    Person.add(id=2).set(full_name="Gottfried Wilhelm Leibniz")
    Person.add(id=3).set(full_name=-1)  # Non-string name


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

# Set a initials property that replaces the name with the first letter of each word.
with model.rule():
    person = Person()
    person.set(initials=re.sub(r"(\w)\w+", r"\1.", person.full_name))

with model.query() as select:
    person = Person()
    response = select(person.id, person.full_name, person.initials)

print(response.results)
#    id                       name  initials
# 0   1                Alan Turing     A. T.
# 1   2  Gottfried Wilhelm Leibniz  G. W. L.
# 2   3                         -1       NaN

See Also

• search()
• match()
• fullmatch()
• findall()