Odp: recode letters to numbers

Hi

If you had your variables as factors you can change levels of each factor.

levels(some.factor) <- c(0,25,50,27,100)

fac<-factor(sample(LETTERS[1:5],20, replace=TRUE)  )
fac
 [1] A A D A D A D A C B A A D D D B D E C B
Levels: A B C D E
 levels(fac)<-1:5
fac
 [1] 1 1 4 1 4 1 4 1 3 2 1 1 4 4 4 2 4 5 3 2
Levels: 1 2 3 4 5
as.numeric(fac)
 [1] 1 1 4 1 4 1 4 1 3 2 1 1 4 4 4 2 4 5 3 2

If you want to do it for whole data frame, you can use cycle or 
lapply/sapply

Regards
Petr
 



r-help-bounces at r-project.org napsal dne 03.12.2010 15:25:17:

Hello,

I have a dataframe assigning various scores on around 20 variables to a 

list of

countries. The scores are rated on a scale of (D, C, B, A) and there are 

also

some not rated ones (NR) and others are left blank (NA). I now wanted to 

transfer the scores into numeric values (such as NR=0, D=25, C=50, B=27, 

A=100),

while also leaving the NA in the dataframe. Can I transform the whole 

dataframe

at once or do I need to transform each column separately? How do I 

correctly

specify the levels and labels of the new dataframe?

Thank you so much,

Katharina



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