What is the difference between lists and tuples?

[Cobra]

What is the difference between lists and tuples?

Code

>>> a = (1, 2, 3)
>>> a
(1, 2, 3)
>>> b = [1, 2, 3]
>>> b
[1, 2, 3]

They look the same to me.

[Alter Lobo]

Lists, tuples and strings are sequences. All of them can be indexed.

Indexing a string:

Code

>>> s = 'abc'
>>> print s[0], s[1], s[2]
a b c

Indexing a tuple:

Code

>>> t = (1, 2, 3)
>>> print t[0], t[1], t[2]
1 2 3

The same with a list:

Code

>>> l = [1, 2, 3]
>>> print l[0], l[1], l[2]
1 2 3

Tuples and strings are immutable and lists are mutable. If I try to change a tuple or a string I get an error while I can do it with a list:

Code

>>> s[1]= 'x'
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: object does not support item assignment
>>>
>>> t[1] = 9
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: object does not support item assignment
>>>
>>> l[1] = 9
>>> l
[1, 9, 3]