One more important difference between tuple and list that's worth knowing about: syntax. Ned makes it seem like tuples have the syntax "(x, y)", but they actually have the syntax "x, y".
I find that a lot of Python programmers, even long-time ones, don't realize this important difference. It's what allows one to write code constructions like "x, y = 1, 2" or "return 1, 2".
One needs the parentheses only to "clarify" this syntax in certain cases; for example, as dict keys, the parens are necessary -- "x = {(1, 2): 2}". Although interestingly, for dict lookup, they are not -- "x[1, 2] == 2".
One way I remind myself of this rule is to realize that "x = 1," is the same as "x = (1,)", but "x = (1)" is actually the same as "x = 1". This is quite different from lists, who are syntactically defined by the "[]" brackets, and thus you require them, or a "list()" call, whenever you make lists, making it just that much more heavyweight as a data structure.
When I used to write python "x = 1," bit me way more than it should have. And I don't see why you wouldn't want to be explicit about your tuple construction every time..
One more important difference between tuple and list that's worth knowing about: syntax. Ned makes it seem like tuples have the syntax "(x, y)", but they actually have the syntax "x, y".
I find that a lot of Python programmers, even long-time ones, don't realize this important difference. It's what allows one to write code constructions like "x, y = 1, 2" or "return 1, 2".
One needs the parentheses only to "clarify" this syntax in certain cases; for example, as dict keys, the parens are necessary -- "x = {(1, 2): 2}". Although interestingly, for dict lookup, they are not -- "x[1, 2] == 2".
One way I remind myself of this rule is to realize that "x = 1," is the same as "x = (1,)", but "x = (1)" is actually the same as "x = 1". This is quite different from lists, who are syntactically defined by the "[]" brackets, and thus you require them, or a "list()" call, whenever you make lists, making it just that much more heavyweight as a data structure.