API Reference
tuple

dbzero.tuple(iterable=())

Creates a persistent, immutable sequence object that behaves like Python's built-in tuple. This object is managed by dbzero, making its contents and the relationships between them part of the persistent data layer.

Parameters

NameTypeDescription
iterableobjectOptional. An iterable (e.g., a list, tuple, or generator) used to initialize the tuple's elements. If not provided, an empty dbzero.tuple is created.

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The method requires that the argument, if provided, is an iterable. Passing non-iterable types (e.g., int, None) or more than one argument will raise a TypeError.

Returns

A dbzero.types.Tuple object. This object supports standard tuple operations, including indexing, iteration, unpacking, comparison, and methods like count() and index().

Side Effects

  • Reference Management: A dbzero.tuple holds strong references to any dbzero objects it contains. If an object that contains a dbzero.tuple is deleted with dbzero.delete(), the dbzero objects inside that tuple will also be deleted from the database upon dbzero.commit().

Examples

Basic Creation and Usage

You can create a dbzero.tuple from any Python iterable. If you call it with no arguments, you get an empty tuple.

# Create an empty tuple
empty_tuple = db0.tuple()
print(len(empty_tuple))
# Expected output: 0
 
# Create a tuple from a list
# It can store various data types, including bytes
my_tuple = db0.tuple([1, "hello", b"world", True])
print(my_tuple[1])
# Expected output: "hello"
 
# Create from a generator expression
gen_tuple = db0.tuple(i for i in range(3))
print(gen_tuple == (0, 1, 2))
# Expected output: True

Standard Tuple Operations

A dbzero.tuple behaves just like a regular Python tuple. You can iterate over it, unpack it, and use its methods.

data_tuple = db0.tuple(['apple', 'banana', 'cherry', 'banana'])
 
# Unpacking
a, b, c, d = data_tuple
print(b)
# Expected output: 'banana'
 
# Methods: count() and index()
print(f"Count of 'banana': {data_tuple.count('banana')}")
# Expected output: Count of 'banana': 2
 
print(f"Index of 'cherry': {data_tuple.index('cherry')}")
# Expected output: Index of 'cherry': 2
 
# Comparison with a standard Python tuple
assert data_tuple == ('apple', 'banana', 'cherry', 'banana')
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