Update a Value in One Column Based on Criteria in Other Columns

Question

If my data frame (df) looks like this:

Name        State
John Smith  MI
John Smith  WI
Jeff Smith  WI

I want to rename the John Smith from

Answer 1

You can also use package data.table:

library(data.table)
setDT(df)[State=="WI", Name:=paste0(Name,"1")]