R help - Jan 2013 - Order variables automatically

Hi,

I have a dataset with 6 categorical variables. I have used this following code
to make the variables u1-u6 ordered factors and this works well.


cat1cat2 cat3 cat4 cat5 cat6 
? 0 ? ?? 1 ? ? 1????? 0 ??? 0? ?? 1
? 1 ? ?? 1 ? ? 0 ? ?? 0 ? ? 0 ? ? 0
.......
....


############
data<-read,table("example.txt")

data <- as.data.frame(lapply(data, ordered)) 

############

Now, suppose I have bigger dataset where some variables are categorical (cat)
and others are continuous (cont)..

cat1 cat2 cont1 cont2 ...cont10 cat3 cont11....cat 40 cont25? etc.


Is there a way to code so that R goes through each variable and orders a
variable if it is categorical and leaves a variable alone if it is continuous?


Thanks,

?Debs

# create an example data frame
yourdata <-
    data.frame(
        cat1 = c( 1 , 0 , 1 ) ,
        cont1 = c( 0 , 1 , 0 ) ,
        cat2 = c( 0 , 0 , 1 )
    )
# if this doesn't work for you,
# please ?dput some example data in the future :)

# figure out which variables contain the word 'cat'
vars.to.order <- grep( 'cat' , names( yourdata ) )

# convert all of those columns to factor..
yourdata[ , vars.to.order ] <- lapply( yourdata[ , vars.to.order ], factor )
# ..and then to ordered factor
yourdata[ , vars.to.order ] <- lapply( yourdata[ , vars.to.order ], ordered
)

# confirm the results of the new data frame
class( yourdata )  # yourdata is a data frame..

sapply( yourdata , class )  # here's the class of each column

yourdata  # here's the whole data set printed to the screen

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