Steven D'Aprano wrote: > On Thu, 09 Nov 2006 03:31:02 -0800, John Machin wrote: > > > > > Bruno Desthuilliers wrote: > >> Gabriel Genellina wrote: > >> > At Wednesday 8/11/2006 22:29, zeal elite wrote: > >> > > >> >> I am looking for substring search python program without using the > >> >> built in funtions like find, or 'in'. > >> > > >> > The only reasonable usage for such a constraint would be a school > >> > assignment so: don't cheat and do your homework! > >> > > >> > >> OTHO, looking for existing solutions to a same or similar problem and > >> studying them is usually considerer good practice in real-life > >> programming jobs !-) > >> > > > > Looking at an existing solution for substring search that was coded in > > Python, instead of using the built-in functionality would IMHO be > > considered extremely bad practice in a real-life programming job. > > Sure. But what if the data type in question wasn't a string, but a list? > > > Given a source list, find the offset of a target sub-list within the > source list, in other words, find for lists. > > i.e. search(source, target) returns n if source[n:n+len(target)] == target > for any sequence type. >
In that case, in a real-life enterprisey environment, you'd just code up the brute-force naive method and wait till someone screamed about the speed. If that happened, you'd have a look at how "find" was implemented for unicode, because it can't use any tricks that depend on there being a small number (e.g. 256) of symbols in the alphabet, and/or you'd fire up your googler and see what had been done outside Python ... > Yes, I know I'm changing the constraints of the problem. (a) There wasn't a problem to start with. (b) It's called "moving the goalposts". > Now for a real > challenge, change the search from a one-dimensional data structure to two. > > (The solution is left as an exercise for the class.) The class knows all about Google. Better leap into the seat of your plagiarism detection machine and start pedalling :-) -- http://mail.python.org/mailman/listinfo/python-list
