Tuple Syntax

A tuple is an ordered, immutable sequence of values. Once created, its elements cannot be changed.

Creating Tuples

Write a tuple with parentheses and commas:

point = (3, 7)
rgb = (255, 128, 0)
empty = ()

Parentheses are optional in most contexts — the comma is what makes a tuple. Try it live and confirm that the comma alone creates a tuple:

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>>> point = 3, 7        # also a tuple
>>> print(type(point))
<class 'tuple'>

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A single-element tuple requires a trailing comma; without it, Python treats the parentheses as grouping. Run this and edit the values to see how the trailing comma changes the type:

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>>> one = (42,)         # tuple with one element
>>> not_one = (42)      # just the integer 42
>>> print(type(one), type(not_one))
<class 'tuple'> <class 'int'>

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Indexing and Length

Tuples support indexing, slicing, and len() exactly like lists. Try it live and edit the indices:

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>>> rgb = (255, 128, 0)
>>> print(rgb[0])        # 255
255
>>> print(rgb[-1])       # 0
0
>>> print(len(rgb))      # 3
3

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Immutability

Attempting to change an element raises a TypeError:

rgb = (255, 128, 0)
rgb[0] = 100     # TypeError: 'tuple' object does not support item assignment

Tuples vs. Lists

Tuple	List
Immutable	Mutable
(1, 2, 3)	[1, 2, 3]
Can be a dict key	Cannot be a dict key
Slightly faster	More flexible

Use a tuple when the structure is fixed by design: a coordinate, an RGB colour, a database record field.

Use a list when items will be added, removed, or reordered.

Converting Between Tuples and Lists

Try it live and watch the list grow before it is converted back:

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>>> t = (1, 2, 3)
>>> lst = list(t)       # convert tuple -> list
>>> lst.append(4)
>>> t2 = tuple(lst)     # convert list -> tuple
>>> print(t2)
(1, 2, 3, 4)

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