Hi Michael, Thanks a lot!
Best, Nicola Michael Bedward ha scritto:
Hi Nicola, Although you have subsetted the data.frame, the factor variable will still include the empty level. For example, the following... foo <- data.frame(f = factor(c("a", "b", "c", "b", "a")), val = 1:5) foo2 <- foo[ foo$f != "a", ] foo2 str(foo2) Produces this output... f val 2 b 2 3 c 3 4 b 4 'data.frame': 3 obs. of 2 variables: $ f : Factor w/ 3 levels "a","b","c": 2 3 2 $ val: int 2 3 4 You can drop the unused factor level "a" like this... foo2$f <- foo2$f[, drop=TRUE] str(foo2) 'data.frame': 3 obs. of 2 variables: $ f : Factor w/ 2 levels "b","c": 1 2 1 $ val: int 2 3 4 Michael On 15 August 2010 22:03, Nicola Spotorno <nicola.spoto...@isc.cnrs.fr> wrote:Hello, thanks for your replies, but the logic operator is '!='. If I call sentence_trial the dataframe shows no 'an' datapoints as I want but I still have problems with 'str' and 'interaction_plot'. Nicola
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