Question

Let’s say I have a data frame looking like this:

Value1   Value2
1        543
1        845
3        435
5        724
5        234
8        204

Now, I would like the first column to count up sequentially, instead of jumping several steps every time the value changes, like so:

Value1   Value2
1        543
1        845
2        435
3        724
3        234
4        204

If there was some way of simply replacing an element in a data frame with something else, this could be easily done. However, I don’t know if there is such a command. Also, I guess some kind of macro command for doing something like this would do, but I guess there isn’t such a command.

Answer 1

Make use of the fact that factor levels will be increasing integers:

> x <- c(1, 1, 3, 5, 5, 8)
> as.numeric(factor(x))
[1] 1 1 2 3 3 4