Dummy (factor) based on a pair of variables
On 2009.04.18 15:58:30, Jason Morgan wrote:
On 2009.04.18 13:52:35, Serguei Kaniovski wrote:
I can generate the above dummies but can this design be imputed in a reg. model directly?
Oops, I apologize for not reading the whole question. Can you do the
following:
lm(y ~ I(ifelse(df$i=="AUT"|df$j=="AUT", 1, 0)) +
I(ifelse(df$i=="BEL"|df$j=="BEL", 1, 0)) +
I(ifelse(df$i=="GER"|df$j=="GER", 1, 0)), data=df)
If you exclude the ifelse(), you will get a vector of TRUE/FALSE,
which may or may not work.
~Jason
Hello Serguei,
I am sure there is a better way to do this, but the following seems to
work:
# Create sample data.frame()
i <- c("AUT", "AUT", "BEL")
j <- c("BEL", "GER", "GER")
df <- data.frame(i=i, j=j)
# Create dummy vectors
df$d.aut <- ifelse(df$i=="AUT"|df$j=="AUT", 1, 0)
df$d.bel <- ifelse(df$i=="BEL"|df$j=="BEL", 1, 0)
df$d.ger <- ifelse(df$i=="GER"|df$j=="GER", 1, 0)
# Print results
df
HTH,
~Jason
-- Jason W. Morgan Graduate Student, Political Science *The Ohio State University*