@grasso wrote:
Hi, I am following up on an existing thread opened last 2015 with a new question in 2018 that somehow seemed to be left unanswered: Error : cannot rescale a constant/zero column to unit variance. Basically I am trying to convert categorical variables using one hot encoding and then feeding all the predictors (as.numeric) into prcomp() function but got the error: “error in prcomp.default(training_setx[-19], center = T, scale. = T) : cannot rescale a constant/zero column to unit variance”. I know the issue is with columns having constant 0 but that is precisely what one hot encoding does, so how can I overcome this issue to apply pca? I tried scaling the variable after one hot encoding but still received the same error. This is a sample of my script:
My_Data$My_variable = to_categorical(as.numeric(My_Data$My_variable)) #works fine
prcomp(My_Data, center=T, scale.=T) # RETURNS THE ERROR!
Also a question I have, is it correct to apply one hot encoding to categorical predictors in this case or would just suffice turning them in numeric? Thanks very much and hope to be hearing from you…
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