Aggregate by factor levels, keeping other variables in the resulting data frame

Question

I\'m trying to calculate the minimum values of a numeric column for each level of a factor, while keeping values of another factor in the resulting data frame.

Answer 1

You need to use merge on result of aggregate and original data.frame

merge(aggregate(value ~ code, dat, min), dat, by = c("code", "value"))
##   code value   index
## 1 HH11  24.1  023434
## 2 HH45  37.2 3377477
## 3 JL03  20.0 1177777