[Tutor] Tuple

[Kaushal Shriyan]

On 4/11/06, Noufal Ibrahim <noufal at nibrahim.net.in> wrote:
>
> On Tue, April 11, 2006 2:49 pm, Kaushal Shriyan wrote:
> > Hi All
> >
> > I am referring to http://www.ibiblio.org/obp/thinkCSpy/chap09.htm
> >
> >>>> tuple = ('a', 'b', 'c', 'd', 'e')
> >>>> tuple[0]
> > 'a'
> >
> >
> > And the slice operator selects a range of elements.
> >
> >>>> tuple[1:3]
> > ('b', 'c')
> >
> >
> > But if we try to modify one of the elements of the tuple, we get a error:
> >
> >>>> tuple[0] = 'A'
> > TypeError: object doesn't support item assignment
> >
> >
> > Of course, even if we can't modify the elements of a tuple, we can
> > replace it with a different tuple:
> >
> >>>> tuple = ('A',) + tuple[1:]
> >>>> tuple
> > ('A', 'b', 'c', 'd', 'e')
> >
> > How does tuple = ('A',) + tuple[1:]  this work ????
>
> One question mark is enough. ;)
>
> ('A',) creates a tuple with a single element. The comma at the end is to
> differentiate between a tuple and just grouping brackets.
> tuple[1:] returns all elements of the tuple except the first.
> So what do you have?
> A tuple ('A') and another tuple ('b', 'c', 'd', 'e').
>
> Now, the + operator concatenates these two into a new tuple. What do you get?
> ('A','b','c','d','e').
>
> This is returned by the expression on the right hand side. And it's
> assigned to the variable "tuple". When you print it, you get the value.
>
> I think you're getting confused between changing a tuple itself and
> creating a new one with pieces of others.
>
> On a side note, it's not a good idea to call a variable "tuple" since
> there is a python builtin by the same name.
> --
> -NI
>
>

Thanks Noufal for the explanation

Appreciate it

Kaushal