Sorry for not elaborating in the first place (I was trying to make the point very concise).
This is the starting city : Philadelphia This are the other cities : Chicago, Boston, Austin The itinerary is the concatenation of starting city + other cities to be visited : [Philadelphia, Chicago, Boston, Austin] In this contrived example the first city is fixed, because this is where I am now, wherever I decide to go next. That's why I decide to reorder all cities of my itinerary except the first one. This is what my naive code what trying to achieve (expected value of slice itinerary after partial sort) : [Philadelphia Austin Boston Chicago] This is what the code actually produces (value of slice itinerary after partial sort) : [Philadelphia Boston Chicago Austin] , which is why i say it is broken : the last 3 items don't end up in alphabetical order like I expected them to be. In a real program, there would be various legit reasons to sort only part of a slice, and the items would not always have a builtin type like string, rather custom struct types. @CBanning Thanks, I had not thought of StringSlice! But it's not applicable in my real programs, which deal with custom struct types (not strings). @David Sorting the whole slice is not what I was trying to achieve, because I can't change my starting point. The bug in my code is that the two arguments I pass to sort.Slice are inconsistent : the portion to be sorted is a reslicing from itinerary, while the "less" closure indexes items of the whole itinerary. I brought up the "go vet" idea because I feel that whenever someone will do some reslicing directly in the first argument, - either the result will be "broken" like mine, - or the code in the less function will have to refer to the same (unnamed) resliced portion, which is imo convoluted : fix 1 <https://play.golang.org/p/v0V8BQuJ_m> or fix 2 <https://play.golang.org/p/z_52IQAhY4> . The most readable alternative I can think of while still using sort.Slice is to reslice in a new variable prior to sorting : fix 3 <https://play.golang.org/p/ZgHyGOLiQO> . Best regards Val On Wednesday, March 8, 2017 at 3:25:48 PM UTC+1, David Peacock wrote: > > On Wed, Mar 8, 2017 at 8:32 AM, Valentin Deleplace <dele...@gmail.com > <javascript:>> wrote: > >> I did explain the expected result : "and I want to visit other cities in >> alphabetical order" >> > > Jan is correct; the characterization of a problem hinges on accurately > describing what you expect and what happened instead. Terms such as > "broken" and "does not work" are best avoided because others don't know > what your definitions are for these in the given context. :-) > > That being said, your alphabetical order is returned as you intend if you > adjust line 17 thusly: > > sort.Slice(itinerary[:], func(i, j int) bool { > > Cheers, > David > > >> >> Le 8 mars 2017 2:16 PM, "Jan Mercl" <0xj...@gmail.com <javascript:>> a >> écrit : >> >>> On Wed, Mar 8, 2017 at 2:10 PM Val <dele...@gmail.com <javascript:>> >>> wrote: >>> >>> > What do you think? >>> >>> You should explain what you've expected to get instead of what you've >>> got. Without that, I for one, cannot figure out what you see as broken and >>> I have no idea why do you think it's not a good idea to sort a slice of a >>> slice. After all, it's just a slice as any other. >>> >>> -- >>> >>> -j >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
