Change letter case of column names

Easy Solution

names(DF) <- toupper(names(DF))

Here is a one-liner implementing "the easiest way to match column names among data sets" that I can think of:

## Columns 1:3 left unaltered since they are not place names.
names(my.data2)[-1:-3] <- tolower(names(my.data2)[-1:-3])

## View the results
names(my.data2)
# [1] "landuse"       "units"         "grade"         "clay"         
# [5] "lincoln"       "basinandrange" "mccartney"     "maple"   

modern solution

This is now a job for janitor::clean_names(), just choose case parameter that fits you need.