in place-ness of list.append

[Kent Johnson]

Bart Van Loon wrote:
> Hi all,
> 
> I would like to find out of a good way to append an element to a list
> without chaing that list in place, like the builtin list.append() does.
> 
> currently, I am using the following (for a list of integers, but it
> could be anything, really)
> 
> #--------------------------------------------------
> def addnumber(alist, num):
>     """ work around the inplace-ness of .append """ 
>     mylist = alist[:]
>     mylist.append(num)
>     return mylist
> #--------------------------------------------------

Use + :

In [1]: a=[1,2]

In [2]: b=a+[3]

In [3]: a
Out[3]: [1, 2]

In [4]: b
Out[4]: [1, 2, 3]

Kent