"Diez B. Roggisch" <[EMAIL PROTECTED]> wrote, oder schrieb, of het geskryf:
| Hendrik van Rooyen schrieb: | > Hi, | > | > for S where S is a Standard Python type: | > The slice notation S[n] returns either: | > The n'th element of S, or | > The value of the dictionary entry whose key is n. | > | > This is beautiful because as a programmer you don't have to worry what S is... | > (and as an aside - This consistency has already saved my butt when I thought I | > was working with a string that turned out to be a tuple instead - and still | > worked perfectly as expected...) | > | > Now consider what you have to do to add an element to S... | > (where "add" is used in its meaning of increasing the size of a set, and not 1 + | > 1 = 2) | > | > There seems to be no common methods such as- | > "prepend" - for adding something to the beginning | > "append" - for adding something to the end | > "insert[j]" - for adding something somewhere in the middle | > | > Or have I missed something ? | | Yes, the nature of collections. dictionaries have no notion of | "somewhere in the middle". Most of the time they are unordered. If they | are ordered, they can be ordered by insertion time, key or value value. | And they always need key, value | | So - all these three methods only make sense on sequences which imply a | key (the index), and are mutable of course - which is why they are | available on lists only. | | Diez I understand that dicts are actually a bit special - Its very simple to add something to a dict - you just do it - but the in the other cases what I have in mind is more in line with some of what Paul Boddie wrote... - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
