replace NA value with the group value

Question

I have a df as follows which has 20 people across 5 households. Some people within the household have missing data for whether they have a med_card or not. I want to give th

Answer 1

This is late, but if are working on a numeric column, try this:

require(data.table)

setDT(df)[,'record_year':=mean( med_card,na.rm = T),by = c('hhold_no')]