### Name: ExpressionSet
### Title: Class to Contain and Describe High-Throughput Expression Level
###   Assays.
### Aliases: class:ExpressionSet ExpressionSet ExpressionSet-class
###   exprs,ExpressionSet-method exprs<-,ExpressionSet,matrix-method
###   geneNames,ExpressionSet-method
###   geneNames<-,ExpressionSet,character-method
###   initialize,ExpressionSet-method coerce,exprSet,ExpressionSet-method
###   coerce,eSet,ExpressionSet-method
###   coerce,ExpressionSet,data.frame-method
###   updateObject,ExpressionSet-method as.data.frame.ExpressionSet
### Keywords: classes

### ** Examples

# create an instance of ExpressionSet
new("ExpressionSet")

# update an existing ExpressionSet
data(sample.ExpressionSet)
updateObject(sample.ExpressionSet)

# update existing exprSet-like class to ExpressionSet
data(sample.exprSet)
expressionSet <- as(sample.exprSet,"ExpressionSet")
expressionSet

# information about assay and sample data
featureNames(expressionSet)[1:10]
sampleNames(expressionSet)[1:5]
phenoData(expressionSet)
experimentData(expressionSet)

# subset: first 10 genes, samples 2, 4, and 10
expressionSet <- as(sample.exprSet,"ExpressionSet")
expressionSet[1:10,c(2,4,10)]

# named features and their expression levels
subset <- expressionSet[c("AFFX-BioC-3_at","AFFX-BioDn-5_at"),]
exprs(subset)

# samples with above-average 'score' in phenoData
highScores <- expressionSet$score > mean(expressionSet$score)
expressionSet[,highScores]

# (automatically) coerce to data.frame
lm(score~AFFX.BioDn.5_at + AFFX.BioC.3_at, data=subset)