in_()#

relationalai.InstanceProperty
InstanceProperty.in_(others: Iterable[Any]) -> Expression

Checks if any of the values produced by InstanceProperty are contained in others. Returns an Expression that filters objects and property values based on their membership in the others iterable. Must be used in a rule or query context.

Parameters#

NameTypeDescription
othersIterable[Any]Collection of values for checking membership. Supports Producer objects, numbers, strings, dates, and datetime objects.

Returns#

An Expression object that filters objects and property values based on their membership in the others collection.

Example#

Use .in_() to filter objects in a rule or query context, checking if their property values exist within a specified collection:

import relationalai as rai

# Create a model named "books" with a Book type.
model = rai.Model("books")
Book = model.Type("Book")

# Add some books to the model.
with model.rule():
    Book.add(title="Foundation", author="Isaac Asimov")
    Book.add(title="Cat's Cradle", author="Kurt Vonnegut")
    Book.add(title="Dune", author="Frank Herbert")

# Get the titles of books written by Kurt Vonnegut or the author of Foundation.
with model.query() as select:
    book = Book()  # Get all book objects.
    book.author.in_(["Kurt Vonnegut", Book(title="Foundation").author])  # Filter books by author in the collection.
    response = select(book.title, book.author)  # Select the title and author properties of the books.

print(response.results)
# Output:
#           title         author
# 0  Cat's Cradle  Kurt Vonnegut
# 1    Foundation   Isaac Asimov

In the above example, book is an Instance that produces Book objects. book.author.in_() returns an Expression that filters books to include only those authored by "Kurt Vonnegut" or the author of "Foundation".

If no authors from the collection match, the query yields no results:

with model.query() as select:
    book = Book()  # Get all book objects.
    book.author.in_(["Ted Chiang", "J.R.R. Tolkien"])  # Filter books by author in the collection.
    response = select(book.title, book.author)  # Select the title and author properties of the books.

print(response.results)
# Output:
# Empty DataFrame
# Columns: []
# Index: []

.in_() also works with multi-valued properties, such as properties created with .add() or .extend():

# Add genres to the books.
# The genre property is multi-valued because it is created with Instance.extend().
with model.rule():
    Book(title="Foundation").genres.extend(["Science Fiction", "Space Opera"])
    Book(title="Cat's Cradle").genres.extend(["Science Fiction", "Satire"])
    Book(title="Dune").genres.extend(["Science Fiction", "Space Opera"])

# Get books with the genre "Satire", "Fantasy", or both.
with model.query() as select:
    book = Book()  # Get all book objects.
    book.genres.in_(["Satire", "Fantasy"])  # Filter books by genre in the collection.
    response = select(book.title, book.author, book.genres)  # Select the title and genre properties of the books.

print(response.results)
# Output:
#           title         author  genres
# 0  Cat's Cradle  Kurt Vonnegut  Satire

Note that only the "Satire" genre appears in the results. This is because book.genres produces multiple values, and .in_() filters both the book objects and their genres. Consequently, only genres that meet the filter criteria are included in the final results.

See Also#