for loop - Writing data from one dataframe to a new column of another in R -
this question has answer here: how join (merge) data frames (inner, outer, left, right)? 12 answers i have 2 data frames in r. data , frame monthly sales per department in store, looks this: while averages , frame average sales on months per department, looks this: what i'd add column data containing average sales (column 3 of averages ) each department. whereas have avg column zeroes, i'd contain overall average sales whatever department listed in row. code have now: for(j in 1:nrow(avgs)){ for(i in 1:nrow(data)){ if(identical(data[i,4], averages[j,1])){ gd[i,10] <- avgs[j,3] } } } after running loop, avg column in data still zeroes, makes me think if(identical(data[i,4], averages[j,1])) evaluating false ... why be? how can troubleshoot issue / there better way this? are looking merge function? merge(x = data, y =