R Language Foundation Memo

Reference: "R language Combat"

1. Get Help

Help.start ()	Open the Help document home page
Help ("foo") or? foo	See Help for function foo (quotation marks can be omitted)
Help.search ("foo") or?? Foo	Search for local help documents with Foo as a keyword
Example ("foo")	Example of use of function foo (quotation marks can be omitted)
Rsitesearch ("foo")	Search online documents and mailing list archives with foo as keyword
Apropos ("foo", mode= "function")	List all available functions with Foo in the name
Data ()	Lists all available sample datasets included in the currently loaded package
Vignette ()	List all vignette documents available in the currently installed package
Vignette ("foo")	Displays the specified vignette document for theme Foo

Help.start ()

Open Document Home http://127.0.0.1:27064/doc/html/index.html

Help ("foo") or? foo

Foo is an existing function in R that opens the description document of the function directly.

Data ()

Lists all available sample datasets in the loaded package, and the data listed here is as straightforward to use as the datasets listed in LS (), but the LS () method does not list these datasets.

2. Working space

GETWD ()	Displays the current working directory
SETWD ("Mydirectory")	Modify the current working directory to Mydirectory
LS ()	List objects in the current workspace
RM (ObjectList)	Remove (delete) one or more objects
Help (Options)	Show description of available options
Options ()	Show or set current options
History (#)	Show the most recently used # commands (default is 25)
SaveHistory ("MyFile")	Save the command history to file MyFile (the default value is. Rhistory)
LoadHistory ("MyFile")	Loads a command history file (the default value is. Rhistory)
Save.image ("MyFile")	Save the workspace to file MyFile (the default value is. RData)
Save (ObjectList, file= "MyFile")	Saves the specified object to a file
Load ("MyFile")	Reads a workspace into the current session (the default value is. RData)
Q ()	Exit R. You will be asked if you want to save your workspace

SETWD ("Mydirectory")

SETWD () only changes the working directory, and then opens R when the working directory is back to the previous default working directory.

RM ()

Use the RM () method to delete all object methods in the Working Environment RM (LIST=C (LS (all=true))).

3. Graphics output

PDF ("Filename.pdf")	PDF file
Win.metafile ("Filename.wmf")	Windows Metafile
PNG ("Filename.png")	PBG file
JPEG ("Filename.jpg")	JPEG files
BMP ("Filename.bmp")	BMP file
PostScript ("Filename.ps")	PostScript file

Save the plots area directly as a picture.

4. Manipulating objects

Length (object)	Displays the number of elements/components in the object
Dim (object)	Display the dimensions of an object
Str (object)	Show the structure of an object
Class (Object)	Display the class or type of an object
Mode (object)	Show the mode of an object
Names (object)	Displays the names of the components in an object
C (Object, Object,...)	Merging objects into a vector
Cbind (Object, object, ...)	Merging objects by column
Rbind (Object, object, ...)	Merging objects by rows
Object	Output an Object
Head (object)	List the starting part of an object
Tail (object)	List the last part of an object
LS ()	Displays the current list of objects
Rm (Object, object, ...)	Deletes one or more objects.
NewObject <-Edit (object)	Edit the object and save as NewObject
Fix (object)	Edit objects directly

Object

Output an object that looks better with head () or tail () when the dataset is larger.

Head () and tail ()

The default data is 6 rows, and you can define the amount of data you view. Head (Object,n) and tail (object,n), n is the number you want to see.

Fix (object)

A similar view () looks at the data, Eidt () edits the object.

5.

Different industries have different names for the rows and columns of a dataset. Statisticians call them observations (observation) and variables

(variable), a database analyst calls it record and field, and researchers in the data Mining/machine learning disciplines call them examples (example) and attributes (attribute)

6. Attach (), detach (), with ()

Summary (Mtcars$mpg) plot (mtcars$mpg,mtcars$disp) plot (MTCARS$MPG,MTCARS$WT) #也可写作: Attach (Mtcars) plot (mpg, disp) Plot (mpg, WT) detach (Mtcars) #或者是: With (Mtcars,{summary (MPG,DISP,WT) plot (mpg,disp) plot (mpg, WT)})

The assignment in the WITH () function only takes effect inside the function, which is equivalent to a local variable. To assign a value other than the structure of the WITH () function, you can apply a special assignment symbol <<-instead of <-.

With (Mtcars,{nokeepstas <-summary (MPG) keepstats <<-Summary (MPG)}) nokeepstatskeepstats

7.

Read.table Row.names Properties

Data.frame also has row.names properties

You can define row.names directly when you create a dataset, similar to the Col.names property.

8.

Factor factor

The difference between a common factor and an ordered factor

Status <-c ("Poor", "improved", "excellent", "Poor") #无序status <-factor (status, ordered=f) status

#有序status <-factor (status, ordered=t) status

#自定义顺序status <-Factor (Status,ordered=true,levels=c ("Poor", "improved", "excellent") status

Have any questions proposed welcome, reproduced please indicate the source, thank you!

R Language Foundation Memo