Add Variables to Tuple

Tuples are immutable; you can't change which variables they contain after construction. However, you can concatenate or slice them to form new tuples:

a = (1, 2, 3)b = a + (4, 5, 6)  # (1, 2, 3, 4, 5, 6)c = b[1:]  # (2, 3, 4, 5, 6)

And, of course, build them from existing values:

name = "Joe"age = 40location = "New York"joe = (name, age, location)

You can start with a blank tuple with something like t = (). You can add with +, but you have to add another tuple. If you want to add a single element, make it a singleton: t = t + (element,). You can add a tuple of multiple elements with or without that trailing comma.

>>> t = ()>>> t = t + (1,)>>> t(1,)>>> t = t + (2,)>>> t(1, 2)>>> t = t + (3, 4, 5)>>> t(1, 2, 3, 4, 5)>>> t = t + (6, 7, 8,)>>> t(1, 2, 3, 4, 5, 6, 7, 8)

In Python 3, you can use * to create a new tuple of elements from the original tuple along with the new element.

>>> tuple1 = ("foo", "bar")>>> tuple2 = (*tuple1, "baz")>>> tuple2('foo', 'bar', 'baz')

The byte code is almost the same as tuple1 + ("baz",)

Python 3.7.5 (default, Oct 22 2019, 10:35:10) [Clang 10.0.1 (clang-1001.0.46.4)] on darwinType "help", "copyright", "credits" or "license" for more information.>>> def f():...     tuple1 = ("foo", "bar")...     tuple2 = (*tuple1, "baz")...     return tuple2... >>> def g():...     tuple1 = ("foo", "bar")...     tuple2 = tuple1 + ("baz",)...     return tuple2... >>> from dis import dis>>> dis(f)  2           0 LOAD_CONST               1 (('foo', 'bar'))              2 STORE_FAST               0 (tuple1)  3           4 LOAD_FAST                0 (tuple1)              6 LOAD_CONST               3 (('baz',))              8 BUILD_TUPLE_UNPACK       2             10 STORE_FAST               1 (tuple2)  4          12 LOAD_FAST                1 (tuple2)             14 RETURN_VALUE>>> dis(g)  2           0 LOAD_CONST               1 (('foo', 'bar'))              2 STORE_FAST               0 (tuple1)  3           4 LOAD_FAST                0 (tuple1)              6 LOAD_CONST               2 (('baz',))              8 BINARY_ADD             10 STORE_FAST               1 (tuple2)  4          12 LOAD_FAST                1 (tuple2)             14 RETURN_VALUE

The only difference is BUILD_TUPLE_UNPACK vs BINARY_ADD. The exact performance depends on the Python interpreter implementation, but it's natural to implement BUILD_TUPLE_UNPACK faster than BINARY_ADD because BINARY_ADD is a polymorphic operator, requiring additional type calculation and implicit conversion.