why?

[Brian Quinlan]

> Why does this happen:
> 
> >>> doing = ['a','b','c']
> >>> doing[1] = ('b','c')
> >>> doing[1][0]
> 'b'
> >>> doing[1][0] = 'i'
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
> TypeError: object doesn't support item assignment
> >>>
> 
> Why can't I change that value from 'b' to 'i' ?  Why?

Because, as the exception said, tuples don't support item assignment.

Try changing the second line to:

doing[1] = ['b', 'c']

That will make doing[1] a list, and lists do support item assignment.

Cheers,
Brian