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noamross / zero-dependency-problems

Real-world code problems in R, without dependencies
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apply-on-nonnumeric-columns #21

Open noamross opened 9 years ago

noamross commented 9 years ago

https://github.com/noamross/zero-dependency-problems/blob/master/R/apply-on-nonnumeric-columns.md

I'm having some trouble applying things to a subset of the dataframe I'm using.

Diet121 <- subset(ChickWeight, Diet == 1 & Time == 21)

This works fine, and gives the subset I want, but when I try to apply the mean to the columns, I get an error message

apply(Diet121, 2, mean) weight Time Chick Diet NA NA NA NA Warning messages: 1: In mean.default(newX[, i], ...) : argument is not numeric or logical: returning NA 2: In mean.default(newX[, i], ...) : argument is not numeric or logical: returning NA 3: In mean.default(newX[, i], ...) : argument is not numeric or logical: returning NA 4: In mean.default(newX[, i], ...) : argument is not numeric or logical: returning NA

I'm assuming I'm doing something stupid such as not attaching something correctly. Is something wrong with 'mean'?