there are much faster ways...just a little more intricate. Nando
-- Open WebMail Project (http://openwebmail.org) ---------- Original Message ----------- From: Fernando Cabral <fernandojosecab...@gmail.com> To: mailing list for gambas users <gambas- u...@lists.sourceforge.net> Sent: Sat, 1 Jul 2017 00:18:42 -0300 Subject: Re: [Gambas-user] I need a hint on how to deleted duplicate items in a array > I thank you guys for the hints on counting and eliminating duplicates. In > the end, I resorted to something that is very simple and does the trick in > three steps. In the first step I sort the array. > In the second step I count the number of occurrences and prepend it to the > word itself (with a separator). In the third step I sort the array again, > so now I have it sorted by the number of occurrences from the largest to > the smallest. > > That is all I need. > > Nevertheless, I am concerned with the performance. For 69,725 words, from > which 8,987 were unique, it took 28 seconds for the code below to execute. > I will survive this 28 seconds, if I have to. But I still would like to > find a faster solution. > > On the other hand, I think I am close to the fastest possible solution. > Basically, the array will be traversed once only, no matter how many terms > and how many repetitions it may have. > > (What do you think about this efficiency, Tobi?) > > *MatchedWords.Sort(gb.ascent + gb.language + gb.IgnoreCase) For i = 0 To > MatchedWords.Max n = 1 For j = i + 1 To MatchedWords.Max If > (Comp(MatchedWords[i], MatchedWords[j], gb.language + gb.ignorecase) = 0) > Then n += 1 Else Break Endif Next > UniqWords.Push(Format(n, "0###") & "#" & MatchedWords[i]) i += (n - 1) > NextUniqWords.Sort(gb.descent + gb.language + gb.ignorecase)For i = 0 To > UniqWords.Max Print UniqWords[i]Next* > > 2017-06-30 15:10 GMT-03:00 Gianluigi <bagone...@gmail.com>: > > > Just for curiosity, on my computer, my function (double) processes 10 > > million strings (first and last name) in about 3 seconds. > > Very naif measurement using Timers and a limited number of names and > > surnames eg Willy Weber has come up 11051 times > > > > To demonstrate the goodness of Tobias' arguments, about 1 million 3 cents a > > second I really understood (I hope) what he wanted to say. > > > > Sorry my response times but today my modem works worse than my brain. > > > > Regards > > Gianluigi > > > > 2017-06-30 17:58 GMT+02:00 Gianluigi <bagone...@gmail.com>: > > > > > Sorry Tobias, > > > other explanations are not necessary. > > > I would not be able to understand :-( > > > I accept what you already explained to me as a dogma and I will try to > > put > > > it into practice by copying your code :-). > > > > > > Thanks again. > > > > > > Gianluigi > > > > > > 2017-06-30 17:44 GMT+02:00 Gianluigi <bagone...@gmail.com>: > > > > > >> > > >> 2017-06-30 17:21 GMT+02:00 Tobias Boege <tabo...@gmail.com>: > > >> > > >>> > > >>> I wouldn't say there is anything *wrong* with it, but it also has > > >>> quadratic > > >>> worst-case running time. You use String[].Push() which is just another > > >>> name > > >>> for String[].Add(). Adding an element to an array (the straightforward > > >>> way) > > >>> is done by extending the space of that array by one further element and > > >>> storing the value there. But extending the space of an array could > > >>> potentially > > >>> require you to copy the whole array somewhere else (where you have > > enough > > >>> free memory at the end of the array to enlarge it). Doing worst-case > > >>> analysis, > > >>> we have to assume that this bad case always occurs. > > >>> > > >>> If you fill an array with n values, e.g. > > >>> > > >>> Dim a As New Integer[] > > >>> For i = 1 To n > > >>> a.Add(i) > > >>> Next > > >>> > > >>> then you loop n times and in the i-th iteration there will be already > > >>> i-many elements in your array. Adding one further element to it will, > > >>> in the worst case, require i copy operations to be performed. > > 9-year-old > > >>> C.F. Gauss will tell you that the amount of store operations is about > > >>> n^2. > > >>> > > >>> > > >> Tobias you are always kind and thank you very much. > > >> Is possible for you to explain this more elementarily, for me (a poorly > > >> educated boy :-) ) > > >> > > >> > > >> > > >>> And your function does two jobs simultaneously but only returns the > > >>> result > > >>> of one of the jobs. The output you get is only worth half the time you > > >>> spent. > > >>> > > >>> > > >> I did two functions in one, just to save space, this is a simple > > example. > > >> :-) > > >> > > >> Regards > > >> Gianluigi > > >> > > > > > > > > ------------------------------------------------ ------------ > > ------------------ > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Gambas-user mailing list > > Gambas-user@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/gambas- user > > > > -- > Fernando Cabral > Blogue: http://fernandocabral.org > Twitter: http://twitter.com/fjcabral > e-mail: fernandojosecab...@gmail.com > Facebook: f...@fcabral.com.br > Telegram: +55 (37) 99988-8868 > Wickr ID: fernandocabral > WhatsApp: +55 (37) 99988-8868 > Skype: fernandojosecabral > Telefone fixo: +55 (37) 3521-2183 > Telefone celular: +55 (37) 99988-8868 > > Enquanto houver no mundo uma só pessoa sem casa ou sem alimentos, > nenhum político ou cientista poderá se gabar de nada. > -------------------------------------------------- ---------------------------- > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Gambas-user mailing list > Gambas-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/gambas- user ------- End of Original Message ------- ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
