[R] KNN

Alnazer Elbedairy
Thu, 25 Feb 2016 16:58:57 -0000

Dear All
Divide (same dataset) into 10 folds
fold1 <- nautaData[1:39]
fold2 <- nautaData[40:79]
fold3 <- nautaData[80:119]
fold4 <- nautaData[120:159]
fold5 <- nautaData[160:199]
fold6 <- nautaData[200:239]
fold7 <- nautaData[240:279]
fold8 <- nautaData[280:319]
fold9 <- nautaData[320:359]
fold10 <- nautaData[360:398]
 then
1- conduct 10 fold cross validation on KNN and magorityGuessing function
2- print classification error for both KNN and MPG for every fold
3- print confusion matrix for KNN during each fold
 thank you for help

On Thu, Feb 25, 2016 at 7:32 AM, Ben Tupper <btupper at bigelow.org>
wrote:

> Hi,
>
> Do the knn() or knn1() functions in the 'class' package serve your
purpose?
>
> https://cran.r-project.org/web/packages/class/index.html
>
> Ben
>
> > On Feb 25, 2016, at 9:49 AM, David L Carlson <dcarlson at
tamu.edu> wrote:
> >
> > Perhaps Alnazer is trying to implement "majority vote" kNN:
> >
> >> From Wikipedia
> > (https://en.wikipedia.org/wiki/K-nearest_neighbors_algorithm):
> >
> > In k-NN classification, the output is a class membership. An object is
> classified by a majority vote of its neighbors, with the object being
> assigned to the class most common among its k nearest neighbors (k is a
> positive integer, typically small). If k = 1, then the object is simply
> assigned to the class of that single nearest neighbor.
> >
> > But as Jim said, your function does not do this. It does not even run
> kNN.
> >
> > -------------------------------------
> > David L Carlson
> > Department of Anthropology
> > Texas A&M University
> > College Station, TX 77840-4352
> >
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Jim
> Lemon
> > Sent: Thursday, February 25, 2016 4:15 AM
> > To: Alnazer Elbedairy
> > Cc: r-help mailing list
> > Subject: Re: [R] KNN
> >
> > Hi Alnazer,
> > I'm not surprised that it didn't do what you expected. Even if
I clean
> > up the code so that it will actually run:
> >
> > majorityGuessing<-function(trainingData,categories) {
> >
GuessMPG<-sample(1:length(categories),nrow(trainingData),replace=TRUE)
> > return(GuessMPG)
> > }
> >
> > and call it like this (assuming that you are trying to do something
> > like guessing MPG from the number of cylinders):
> >
> > auto<-read.csv("auto.csv")
> > majorityGuessing(auto$MPG,unique(auto$CYLINDERS))
> >
> > the result is just a sample of 398 integers ranging from 1 to 5, which
> > is not even a guess. Unfortunately, I can't work out what metric
you
> > want to select "nearest neighbors", but perhaps someone else
can.
> >
> > Jim
> >
> > On Thu, Feb 25, 2016 at 5:30 PM, Alnazer Elbedairy
> > <alnazer.elbedairy at gmail.com> wrote:
> >> Dear Jim
> >> thanks you for your kind help.
> >> KNN - is K- Nearest Neighbor, is a technique used in Machine
Learning.
> >> attached you will find a CSV file dataset, my question is :
> >> use the attached Dataset, Use majority guessing technique to
evaluate
> KNN ?
> >> this is the solution I came up with, but I didn't work :-
> >> majorityGuessing <- function(trainingData,categories)
> >> {GuessMPG <- sample(1:length (categories-1,
nrow(testingData),replace=T)
> >> return(GuessMPG)
> >>
> >>
> >>
> >> On Wed, Feb 24, 2016 at 8:18 PM, Jim Lemon <drjimlemon at
gmail.com>
> wrote:
> >>>
> >>> Hi Alnazar,
> >>> I looked at your question yesterday and was unable to find
what a
> >>> "majority guessing" function is. I think it may be
related to the
> >>> "Pandemonium" model of decision making, but that
doesn't get me very
> >>> far. Could you give us a hint as to what this function is?
> >>>
> >>>
> >>
> >> On Wed, Feb 24, 2016 at 8:18 PM, Jim Lemon <drjimlemon at
gmail.com>
> wrote:
> >>>
> >>> Hi Alnazar,
> >>> I looked at your question yesterday and was unable to find
what a
> >>> "majority guessing" function is. I think it may be
related to the
> >>> "Pandemonium" model of decision making, but that
doesn't get me very
> >>> far. Could you give us a hint as to what this function is?
> >>>
> >>> Jim
> >>>
> >>>
> >>> On Wed, Feb 24, 2016 at 7:02 AM, Alnazer <alnazer.elbedairy
at gmail.com>
> >>> wrote:
> >>>> How I can use majority guessing function to evaluate KNN,
if I have
> data
> >>>> saved in CSV file
> >>>>
> >>>> Alnazer Elbedairy
> >>>>
> >>>> ______________________________________________
> >>>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and
more, see
> >>>> https://stat.ethz.ch/mailman/listinfo/r-help
> >>>> PLEASE do read the posting guide
> >>>> http://www.R-project.org/posting-guide.html
> >>>> and provide commented, minimal, self-contained,
reproducible code.
> >>
> >>
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> Ben Tupper
> Bigelow Laboratory for Ocean Sciences
> 60 Bigelow Drive, P.O. Box 380
> East Boothbay, Maine 04544
> http://www.bigelow.org
>
>

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