On Tue, Jun 12, 2018 at 7:42 PM, Clint Hepner <clint.hepner@gmail.com> wrote:
On 2018 Jun 12 , at 10:54 a, Mikhail V <mikhailwas@gmail.com> wrote:
I think it would be logical to have the insert operator for lists. Similar to list extend operator += , it could use one of augmented assignment operators, e,g, /=.
L = ["aa"]
L[0] /= "bb"
-> ["bb", "aa"]
L[0] /= [1,2]
-> [[1,2], "aa"]
-1. There's not much about this that is logical, no matter how much you want an insertion operator. Even if L[0] /= "bb" worked, then logically so should L[0] = L[0] / "bb". However, there is no sense in which L[0] / "bb" by itself has any meaning, and what would L[1] = L[0] / "bb" mean?
And finally, L[0] /= x (and really, every other augmented operator) *already has* a meaning:
Hi Clint, (and others), I must say it is misunderstanding due to my false examples, that I have pasted in original post (I had 2 cloned texts in my text editor and copied the wrong one). I have posted correction just 10 minutes after the original post, see last post. Sorry for confusion! So the idea was about an insert/append operator. Which would use augmented operator. The operator may be /= or ^=. (I like ^= more, so I'll put here example with it). L = [1,2,3] L[0:0] ^= 0 -> [0,1,2,3] L[0:0] ^= -1 -> [-1, 0, 1, 2, 3] L ^= 4 (without index, it works as append() ) -> [-1, 0, 1, 2, 3, 4] As for your question, what would: List1[a:b] = List1[c:d] ^ var mean? (is that what you have asked?) Well, I think this would mean simply : - first append var to List1[c:d] , - then replace the List1[a:b] part with the result. So at least L ^= 4 would make sense as L = L ^ 4. Actually current semantics of += for lists: L += var and L = L + var are different, so it seems to me they were not meant to be bound together.
Note that there is a trick to 'insert' an element with slicing syntax, e.g.:
L[0:0] = [[1,2]]
-> [[1,2], "aa"]
The trick is to put brackets around the element and so it works as insert(). Though additional brackets look really confusing for this purpose, so I don't feel like using this seriously.
It's no more confusing than co-opting an unrelated operator to do the same thing.
If the intention is to insert an element, indeed it is confusing, for me at least: L[0:0] = "bb" -> ["b","b","aa"]