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rreplacerenamer-factor

rename a value in a column according to a condition

I would like to change the name of the entries in the columns of a dataframe when the values of one of the columns are 0. I tried this way, but get an error message. Suppose I would like to change the entries of columns 1,2,3 to "A" when the entries of column 3 are 0

df[ df[ , 3 ] == 0 , c(1,2,4) ] <- "A"

I get 

Warning message:
In `[<-.factor`(`*tmp*`, iseq, value = c("A", "A", "A",  :
  invalid factor level, NA generated
Solution

  • Should work after following command: 

    df[,c(1,2,4)]=sapply(df[,c(1,2,4)], function(x) as.character(x))

    Can be shortened to following as suggested by josilber in the comments:

    df[,c(1,2,4)]=sapply(df[,c(1,2,4)], as.character)