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

Rows and Columns

A number of operators are available to extract data from matrices. The single open square bracket [ is used to one or more elements from a matrix, while the double open square bracket returns just the specific element specified, requiring all relevant subscripts to be supplied.

> ds[1:20,]		        # Rows 1 to 20.
> ds[,5:10]      		# Columns 5 to 10. 
> ds[,c(3,5,8,9)]		# Columns 3, 5, 8, and 9.
> lst[[1]]                      # First element of list lst.

The [ operator can select multiple elements from an object whilst [[ and $ select just a single element.

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