DATA MINING
Desktop Survival Guide by Graham Williams |
|||||
Objects (data, functions, and methods) are searched for through a
search path of packages and datasets. If the object is not found an
error is raised. The search function will list the
current search path. We add elements to the search path with the
attach and library functions and can remove
them with the detach function:
> Species Error: object "Species" not found > search() [1] ".GlobalEnv" "package:Rcmdr" "package:car" [4] "package:tcltk" "package:methods" "package:stats" [7] "package:graphics" "package:grDevices" "package:utils" [10] "package:datasets" "RcmdrEnv" "Autoloads" [13] "package:base" > attach(iris) > search() [1] ".GlobalEnv" "iris" "package:Rcmdr" [4] "package:car" "package:tcltk" "package:methods" [7] "package:stats" "package:graphics" "package:grDevices" [10] "package:utils" "package:datasets" "RcmdrEnv" [13] "Autoloads" "package:base" > Species [1] setosa setosa setosa setosa setosa setosa [...] [145] virginica virginica virginica virginica virginica virginica Levels: setosa versicolor virginica > detach(iris) > search() [1] ".GlobalEnv" "package:Rcmdr" "package:car" [4] "package:tcltk" "package:methods" "package:stats" [7] "package:graphics" "package:grDevices" "package:utils" [10] "package:datasets" "RcmdrEnv" "Autoloads" [13] "package:base" |