Supppose a data.table is:

```
dt <- structure(list(type = c("A", "B", "C"), dates = c("21-07-2011", 
    "22-11-2011,01-12-2011", "07-08-2012,14-08-2012,18-08-2012,11-10-2012"
    )), class = c("data.table", "data.frame"), row.names = c(NA, -3L))

```

Check it:

```
   type                                       dates
1:    A                                  21-07-2011
2:    B                       22-11-2011,01-12-2011
3:    C 07-08-2012,14-08-2012,18-08-2012,11-10-2012

```

I need to add, say, 5 to each of the dates in second column, ie, I want the result to be as under:

```
   type                                       dates
1:    A                                  26-07-2011
2:    B                       27-11-2011,06-12-2011
3:    C 12-08-2012,19-08-2012,23-08-2012,16-10-2012

```

Any help would be appreciated.