I have using quite a large dataset (30+ million IDs) that provides columns for the date of an event:

```
df<- data.frame(id=c("A", "B", "C"), year=c("1955", "1967", "1944"), 
                  month= c("1", "2", "3"), day=c("1", "2", "3")

```

I want to piece these together to form a date. I have been using the following method

```
library(tidyverse)
library(lubridate)

df$date <- paste(df$day, df$month, df$year, sep="-") %>% dmy() 

```

Are there any other ways to do this?

I ask because this appears computationally quite taxing and I cant perform it even if I increase my memory limits.