Nick Coghlan <ncoghlan@gmail.com> writes:

Michael Hudson wrote:

...

partition() works for me. It's not perfect, but it'll do. The idea works for me rather more; it even simplifies the

if s.startswith(prefix): t = s[len(prefix):] ...

How would you do it? Something like:

head, found, tail = s.partition(prefix) if found and not head: ...

I guess I agree that's an improvement - only a slight one, though.

Yes. I seem to fairly often[1] do this with prefix as a literal so only having to mention it once would be a win for me. Cheers, mwh [1] But not often enough to have defined a function to do this job, it seems. -- <teratorn> I must be missing something. It is not possible to be this stupid. <Yhg1s> you don't meet a lot of actual people, do you?

Nick Coghlan wrote:

Another option would be simply "str.part()" and "str.rpart()". Then you could think of it as an abbreviation of either 'partition' or 'parts' depending on your inclination.

I momentarily forgot that "part" is also a verb in its own right, with the right meaning, too (think "parting your hair" and "parting the Red Sea"). So call it +1 for str.part and str.rpart, and +0 for str.partition and str.rpartition. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia --------------------------------------------------------------- http://boredomandlaziness.blogspot.com

Concerning names for partition(), I immediately thought of break(). Unfortunately it's taken. So, how about snap()? head, sep, tail = line.snap(':') -j

Hey guys, don't get lost in random naming suggestions (cut, snap, part, parts, yada yada yada). Each of those is much less descriptive and provides less differentiation from other string methods. Saving a few characters is not worth introducing ambiguity. Also, the longer name provides a useful visual balance between the three assigned variables and the separator argument. As an extreme example, contrast the following: head, found, tail = s.p(separator) head, found, tail = s.partition(separator) The verb gets lost if it doesn't have visual weight. Also, for those suggesting alternate semantics (raising exceptions when the separator is not found), I challenge you to prove their worth by doing all the code transformations that I did. It is a remarkably informative exercise that quickly reveals that this alternative is dead-on-arrival. For the poster suggesting an optional length argument, I suggest writing out the revised method invariants. I think you'll find that it snarls them into incomprehensibility and makes the tool much more difficult to learn. Also, I recommend scanning my sample library code transformations to see if any of them would benefit from the length argument. I think you'll find that it comes up so infrequently and with such differing needs that it would be a mistake to bake this into the proposal. Raymond

Nick> I momentarily forgot that "part" is also a verb in its own right, Nick> with the right meaning, too (think "parting your hair" and Nick> "parting the Red Sea"). If I remember correctly from watching "The Ten Commandments" as a kid, I believe Charlton Heston only parted the Red Sea in one place... Skip

I like partition() but maybe even better would be if strings supported slicing by string indices. key, sep, val = 'foo = 32'.partition('=') would be: key, val = 'foo = 32'[:'='], 'foo = 32'['=':] To me it feels very natural to extend Python's slices to string indices and would cover most of partition()'s use cases. The if sep: idiom of parition() could be solved by throwing an IndexError: e.g: _, sep, port = host.partition(':') if sep: try: int(port) except ValueError: becomes: try: port = host[':':] int(port) except IndexError: pass except ValueError: An advantage of using slices would be that you could specify both a beginning and ending string like this:

...

...

s 'http://192.168.12.22:8080' s['http://':':'] '192.168.12.22'

Sorry if this idea has already been discussed. -- mvh Björn