mergingdf$scheme is a factor, which means it contains both numeric and non-numeric values. To convert it to a numeric type, you can use the as.numeric() function or the factor class with the levels argument.

For example:

mergingdf$scheme <- as.factor(mergingdf$scheme)

or

mergingdf$scheme <- factor(mergingdf$scheme, levels = unique(mergingdf$scheme))

This will convert the scheme values to a numeric type that can be used for analysis.

Last modified on 2023-06-30