I have data (Gr) with 5312 observations. One of the variables (Cr) has 160 missing values (counted from the Excel file). However, none of the following commands seem to help me get the same number of missing values in R.
is.na(Gr$CR) # All False
sum(is.na(Gr$Cr)) # 0
nomissing <- na.omit(Gr$Cr) # N 5312; missing 0
length(subset(Gr, Cr == "")) # 6
Could somebody help with this? The variable is of type "factor".