Hello, how can one merge two data frames when in the second data frame one column defines the start values and another defines the end value of the to be merged range. data.frame.1 time ... 13 24 35 46 55 ... data.frame.2 start end 24 37 ?h? ? ... should result in this 13 NA 24 ?h? 35 ?h? 46 NA 55 ? thanks, René