[R] transform data.frame holding answers --> data.frame holding logicals

saschaview at gmail.com saschaview at gmail.com
Thu Dec 1 19:30:18 CET 2011



I have a data frame, x, holding 5 persons answering the question which 
cars they have used:

# the data frame
x <- as.data.frame(
     c('BMW', '', '',
       'Mercedes', 'VW', '',
       'Skoda', 'VW', 'BMW',
       '', '', '',
       'VW', 'Skoda', ''
       paste( 'v', 1:3, sep='' )

How do I transform this data frame to a data frame stating whether they 
have used the presented car:

    BMW  Mercedes  VW  Skoda
1  T    F         F   F
2  F    T         T   F
3  T    F         T   T
4  F    F         F   F
5  F    F         T   T

My idea was to first find all levels by:

v <- unique(unlist(lapply(x, levels)))

But then I am stuck.

Thanks for help, *S*

Sascha Vieweg, saschaview at gmail.com

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