From: Ron Adam email@example.com
Sent: Monday, January 27, 2014 7:18 PM
On 01/24/2014 07:36 PM, Andrew Barnert wrote:
I was responding to Serhiy's (probably facetious or devil's advocate) suggestion that we should regularize the API: add rfind and rindex to tuple (and presumably Sequence), and those plus rremove to list (and presumably MutableSequence), and so on.
My point was that if we're going to be that radical, we might as well consider removing methods instead of adding them. Some of the find-like methods already take negative indices; expanding that to all of the index-based methods, and doing the equivalent to the count-based ones, and adding a count or index to those that have neither, would mean all of the "r" variants could go away.
How about a keyword to specify which end to index from? When used, it would disable negative indexing as well. When not used the current behaviour with negative indexing would be the default.
direction=0 # The default with the current (or not specified) # negative indexing allowed.
direction=1 # From first. Negative indexing disallowed. direction=-1 # From last. Negative indexing disallowed.
(A shorter key word would be nice, but I can't think of any that is as clear.)
Why does it have to be -1/0/1 instead of just True/False?
In which case we could use "reverse", the same name that's already used for similar things in other methods like list.sort (and that's implied in the current names "rfind", etc.).
The reason for turning off the negative indexing is it would also offer a way to
avoid some indexing bugs as well. (Using negative indexing with a reversed index is just asking for trouble I think.)
But str.rfind takes negative indices today:
>>> 'abccba'.rfind('b', -5, -3) 1
Why take away functionality that already works?
And of course str.find takes negative indices and that's actually used in some quick&dirty scripts:
>>> has_ext = path.find('.', -4)
Of course you could make an argument that any such scripts deserve to be broken…