DATA MINING Desktop Survival Guide by Graham Williams
Desktop Survival Project Home List of Figures List of Tables Data Mining Data Mining Data Mining with Rattle Introduction Data Transform Explore A Model Building Framework Unsupervised Modelling Two Class Models Multi Class Models Regression Models Text Mining Evaluation and Deployment Moving into R Troubleshooting R for the Data Miner R Data Graphics in R Understanding Data Preparing Data Building Models Evaluating Models Algorithms Apriori Bagging Bayes Classifier Boosting Cluster Analysis Conditional Trees Hierarchical Clustering K-Means K-Nearest Neighbours Linear Models Logistic Regression Neural Networks Support Vector Machines Text Mining Open Products AlphaMiner Borgelt Data Mining Suite KNime R Rattle Weka Closed Products C4.5 Clementine Equbits Foresight GhostMiner InductionEngine ODM Enterprise Miner Statistica Data Miner TreeNet Virtual Predict Appendicies Glossary Bibliography Index

Arrays

An array is a vector that in addition has attributes associated with it. Attributes are used in R to record additional information about an object. Consider the simple example of a sequence of numbers (which is a simple vector by default):

> seqv <- 1:20
> is.vector(seqv)
[1] TRUE
> is.array(seqv)
[1] FALSE

> seqa <- as.array(1:20)
> is.array(seqa)
[1] TRUE
> is.vector(seqa)
[1] FALSE

> attributes(seqv)
NULL
> attributes(seqa)
$dim
[1] 20

> seqv@dim
Error: cannot get a slot ("dim") from an object of type "integer"

> seqa@dim
[1] 20

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