references/addrresses in imperative languages
Xah Lee
xah at xahlee.org
Tue Jun 21 02:30:40 EDT 2005
Dear Andrea Griffini,
Thanks for explaning this tricky underneath stuff.
Xah
xah at xahlee.org
∑ http://xahlee.org/
Andrea Griffini wrote:
> On Sun, 19 Jun 2005 22:25:13 -0500, Terry Hancock
> <hancock at anansispaceworks.com> wrote:
>
> >> PS is there any difference between
> >> t=t+[li]
> >> t.append(li)
> >
> >No, but
>
> Yes, a big one. In the first you're creating a new list
> and binding the name t to it, in the second you're extending
> a list by adding one more element at the end.
> To see the difference:
>
> >>> a = [1,2,3]
> >>> b = a
> >>> a = a + [4]
> >>> print a
> [1, 2, 3, 4]
> >>> print b
> [1, 2, 3]
> >>>
> >>> a = [1,2,3]
> >>> b = a
> >>> a.append(4)
> >>> print a
> [1, 2, 3, 4]
> >>> print b
> [1, 2, 3, 4]
> >>>
>
> Andrea
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