Exploring the workspace

The working directory

getwd()

[1] "/home/dwoll/RExREpos/tmp"

setwd("d:/daniel/work/r/")

Create and remove objects

Create some objects - names have to start with a letter. After that, names can contain digits, underscores, and dots. See help(Reserved) for names that cannot be used.

Aval <- 7
Bval <- 15
Cval <- 10
ls()

 [1] "args"         "Aval"         "Bval"         "Cval"         "dirMd"       
 [6] "dirR"         "dirTmp"       "dwKnit"       "fIn"          "fName"       
[11] "fOut"         "gitHubLinks"  "markdEngine"  "postProcess"  "repos"       
[16] "sanitizeMath" "siteGen"     

List available objects

# objects that have a capital C in their name
ls(pattern="C")

[1] "Cval"

exists("Bval")

[1] TRUE

exists("doesNotExist")

[1] FALSE

Remove objects

Aval

[1] 7

rm(Aval)
Aval                             # this will give an error

Error in eval(expr, envir, enclos): object 'Aval' not found

## rm(list=ls(all.names=TRUE))   # remove all objects from the workspace

Show and rename objects

Show objects

Bval

[1] 15

print(Bval)

[1] 15

(Bval <- 4.5)

[1] 4.5

.Last.value

NULL

get("Bval")

[1] 4.5

varName <- "Bval"
get(varName)

[1] 4.5

Rename objects

ls()

 [1] "args"         "Bval"         "Cval"         "dirMd"        "dirR"        
 [6] "dirTmp"       "dwKnit"       "fIn"          "fName"        "fOut"        
[11] "gitHubLinks"  "markdEngine"  "postProcess"  "repos"        "sanitizeMath"
[16] "siteGen"      "varName"     

newNameVar <- "varNew"
assign(newNameVar, Bval)
varNew

[1] 4.5

Environments and search path

search()

 [1] ".GlobalEnv"        "package:stringr"   "package:knitr"    
 [4] "package:stats"     "package:graphics"  "package:grDevices"
 [7] "package:utils"     "package:datasets"  "package:methods"  
[10] "Autoloads"         "package:base"     

How R Searches and Finds Stuff

Session history

By default, savehistory() saves the command history to the file .Rhistory in the current working directory.

history()
savehistory("d:/daniel/work/r/history.R")

By default, save.image() saves all objects in the workspace to the file .RData in the current working directory.

save.image("d:/daniel/work/r/objects.Rdata")

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