[R] Basic SPSS commands in R ?

[Thomas Lumley]

On Sat, 8 Sep 2001, C. Schulz wrote:

> Hello,
> i'm newbie of R and think it is a really good alternative to SPSS.
> But i have more problems using elementary things comparable with using advanced methods.
>
> (1) How can i value label i.e the variable X in data.frame DATA
> with the labels ( 1=very good ) (2=good).
>
> spss syntax when DATA is in Spreadsheet is:
> value labels X
> 1 'very good'.
> 2 'good'.
> execute.

x<-factor(x,labels=c("very good","good"))


> (2) How can i split the data set dependent from one variable and
> give a special output i.e. frequencies.
>
> spss syntax:
> SORT CASES BY countryg .
> SPLIT FILE
> LAYERED BY countryg .
> FREQUENCIES
> VARIABLES=X Y Z
> /ORDER ANALYSIS .
>

Various commands. The easiest is by(), tapply is more general

For example, looking at the Cars93 dataset in the MASS package:

library(MASS)   #load the package
data(Cars93)    #load the dataset

#summaries of all variables by type of car
by(Cars93,Cars93$Type,summary)

##summaries of weight, horsepower and engine size by US/Foreign origin
by(Cars93[,c("Weight","Horsepower","EngineSize")],Cars93$Origin,summary)

## table of no. of cylinders by type for US and Foreign cars.
by(Cars93[,c("Cylinders","Type")], Cars93$Origin, table)


This also gives some more examples of factors (aka VALUE LABELS)


	-thomas

Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

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