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MATLAB R Dictionary
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Transcript of MATLAB R Dictionary
8/6/2019 MATLAB R Dictionary
http://slidepdf.com/reader/full/matlab-r-dictionary 1/17
MATLAB/RDic,onary
RmeetupNYCJanuary72010
HarlanHarris
@HarlanH
MarckVaisman
@wahalulu
MATLABandtheMATLABlogoareregisteredtrademarksofTheMathworks.
8/6/2019 MATLAB R Dictionary
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AboutMATLAB
WhatisMATLAB
• Commercialnumerical
programminglanguage
simula,onandvisualiza,on• Onemillionusers(engineers
scien,stsacademics)
• MATrixLABoratory–
specializesinmatrix
opera,ons
• Mathworks-base&add-ons
• Open-sourceOctaveproject
MATLABHistory
• DevelopedbyCleveMoler
(Math/CSProfatUNM)inthe
1970’sasahigher-levelnumericalprogramming
language(vs.FortranLINPACK)
• Adoptedbyengineersfor
signalprocessingcontrol
modeling• Mul,purposeprogramming
language
8/6/2019 MATLAB R Dictionary
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Notes
• Today’sfocus:CompareMATLAB&Rfordata
analysiscontrastasprogramminglanguages
• MATLABisBaseplusmanytoolboxes
– Baseincludes:descrip,vestatscovarianceand
correla,onlinearandnonlinearregression
– Sta,s,cstoolboxadds:datasetandcategory(like
data.framesandfactors)arraysmorevisualiza,ons
distribu,onsANOVAmul,variateregressionhypothesistests
8/6/2019 MATLAB R Dictionary
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->
• Interac,veprogramming:ScriptsandRead-Evaluate-
PrintLoop
• Similarrepresenta,onsofdata
– Bothusevectors/arraysastheprimarydatastructures• Matlabisbasedon2-Dmatricies;Risbasedon1-Dvectors
– Bothprefervectorizedfunc,onsto for loops
– Variablesaredeclareddynamically
• CandomostMATLABfunc,onalityinR;candomost
Rfunc,onalityinMATLAB.
8/6/2019 MATLAB R Dictionary
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Thebasics:vectorsmatricesandindexing
Task
Createarowvector v=[1234] v<-c(1,2,3,4)
Createacolumnvector v=[1;2;3;4]orv=[1234]’ v<-c(1,2,3,4)Note:Rdoesnotdistinguish
betweenrowandcolumnvectors
EnteramatrixA A=[123;456] Entervaluesbyrow:
A<-matrix(c(1,2,3,4,5,6),
nrow=2,byrow=TRUE)Entervaluesbycolumn:
A<-matrix(c(1,4,2,5,3,6),nrow=2)
Accessthirdelementofvectorv v(3) v[3]orv[[3]]
AccesselementofmatrixA A(2,3) A[2,3]
“Glue”twomatricesa1anda2
samenumberofrowssidebyside
A=[a1a2] A<-cbind(a1,a2)
“Stack”twomatricesa1anda2
samenumberofcolumns
A=[a1;a2] A<-rbind(a1,a2)
Reshape*matrixAmakingitanm
xnmatrixwithelementstaken
columnwisefromA
A=reshape(A,m,n) dim(A)<-c(m,n)
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Operators
Task
Assignment = <-or=
WholeMatrixOpera,ons: Multiplication:A*BSquarethematrix:A^2Raisetopowerk:A^k
A%*%BA%*%AA%*%A%*%A…
Element-by-element
Opera,ons:
A.*BA./B
A.^k
A*BA/B
A^k
ComputeA-1B A\B A%*%solve(B)
Sums Columnsofmatrix:sum(A)Rowsofmatrix:sum(A,2)
colSums(A)rowSums(A)
Logicaloperators(element-by-
elementonvectors/matrices)
a<b,a>b,a<=b,a>=ba==b
a~=bAND:a&&b
OR:a||b
XOR:xor(a,b)NOT:~a
a<b,a>b,a<=b,a>=ba==b
a!=bAND:a&&b(short-circuit)a&b(element-wise)OR:a||ba|b
XOR:xor(a,b)NOT:!a
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Workingwithdatastructures
Task
Buildastructurevoflengthn
capableofcontainingdifferent
datatypesindifferentelements.
MATLAB:cellarray
R:list
v=cell(1,n)Ingeneral,cell(m,n)makesanm×ncell
array.Thenyoucandoe.g.:v{1}=12
v{2}=’hithere’
v{3}=rand(3)
v<-vector(’list’,n)Thenyoucandoe.g.:
v[[1]]<-12v[[2]]<-’hithere’
v[[3]]<-matrix(runif(9),3)
Createamatrix-likeobjectwith
differentnamedcolumns.
MATLAB:structarray
R:data.frame
avals=2*ones(1,6);yvals=6:-1:1;v=[153237];
d=struct(’a’,avals,’yy’,yyvals,’fac’,v);
v<-c(1,5,3,2,3,7)d<-data.frame(cbind(a=2,
yy=6:1),v)
8/6/2019 MATLAB R Dictionary
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Condi,onalscontrolstructuresloops
Task
or loopsovervaluesinvector
v
fori=vcommand1
command2end
Ifonlyonecommand:for(iinv)
command
Ifmultiplecommands:
for(iinv){command1command2
}
If/elsestatement ifcondcommand1command2
elsecommand3command4
end
MATLABalsohastheelseif
statement.
if(cond){command1command2
}else{command3command4
}
Ruseschained“elseif”
statements.
ifelse()func,on >print(ifelse(c(T,F),2,3))[1]23
8/6/2019 MATLAB R Dictionary
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Help!
Task
Gethelponafunc,on helpfminsearch help(pmin)or
?pmin
Searchthehelpforaword lookforinverse ??inverse
Describeavariable class(a) class(a)str(a)
Showvariablesinenvironment who ls()
Underlyingtypeofvariable whos(‘a’) typeof(a)
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Example:k-meansclusteringofFisherIrisdataFisherIrisDataset
sepal_length,sepal_width,petal_length,petal_width,species5.1,3.5,1.4,0.2,setosa4.9,3.0,1.4,0.2,setosa
4.7,3.2,1.3,0.2,setosa4.6,3.1,1.5,0.2,setosa…
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MatlabandRasprogramminglanguages
Scrip,ngreal-,meanalysis Scrip,ngreal-,meanalysis
File-basedenvironments Filesunimportant
Impera,veprogrammingstyle Func,onalprogrammingstyle(impure)
Sta,callyscoped Dynamicallyscoped
Func,onswithmul,plereturnvalues Func,onswithnamedargumentslazy
evalua,on
EvolvingOOPsystem Mul,plecompe,ngOOPsystems
Canbecompiled Cannotbecompiled
Largelibraryoffunc,ons
Professionaldevelopedcostmoney
Largelibraryoffunc,ons
Varyingqualityandsupport
Canembed(in)manyotherlanguages Canembed(in)manyotherlanguages
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Func,ons
function[a,b]=minmax(z)%onefunctionper.mfile!%assigntoformalreturnnamesa=min(z)b=max(z)
end
%ifminmax.minpath[smallest,largest]=…
minmax([1303])
minmax<-function(c,opt=12){#functionsareassignedto#variablesret<-list(min=min(z),max=max(z))
ret#laststatementis#returnvalue}
#ifminmaxwascreatedincurrent#environmentx<-minmax(c(1,30,3))
smallest<-x$min
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8/6/2019 MATLAB R Dictionary
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Othernotes
• r.matlabpackage
• Graphics
– Matlabhasmuchbeer3-d/interac,vegraphicssupport
– Rhasggplot2andmuchbeersta,s,calgraphics
8/6/2019 MATLAB R Dictionary
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Addi,onalResources
• WillDwinellDataMininginMATLAB
• Computerworldar,cleonCleveMoler
• Mathworks
• Matlabcentral
• ComparisonofDataAnalysispackages(hp://anyall.org/blog/2009/02/comparison-of-data-analysis-packages-r-matlab-scipy-excel-sas-spss-
stata/)• R.matlabpackage
• stackoverflow
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Referencesusedforthistalk
• DavidHiebelerMATLAB/RReferencedocument:
hp://www.math.umaine.edu/~hiebeler/comp/
matlabR.html
• hp://www.cyclismo.org/tutorial/R/index.html
• hp://www.stat.berkeley.edu/~spector/R.pdf
• MATLABdocumenta,on
• hp://www.r-cookbook.com/node/23
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ThankYou!