Excel's SUMIF function in R

Use

aggregate(column which has the numeric value in the dataset ~ column to be filtered, datasetname, function name (sum,mean..etc))

> dd
  count CategoryBudget                    Category    Location
1  2110       6379.274            used_car_dealers     chicago
2  2083       6234.621             new_car_dealers     chicago
3  1972       6052.865 automotive_sales_&_services     chicago
4  1712       4809.133            used_car_dealers los_angeles
5  1477       4530.553    auto_parts_&_accessories     chicago
6  1415       4339.386             new_car_dealers los_angeles
> 
> aggregate(count~Location, dd, sum)
     Location count
1     chicago  7642
2 los_angeles  312

Courtesy :  'http://stackoverflow.com/questions/26049011/r-programming-how-to-filter-then-sum