[R] Add a column to a data frame with value based on the percentile of the row

[Rui Barradas]

Hello,

Combine quantile() with findInterval(). Something like the following.


# sample data
x <- rnorm(100)

val <- c("Bottom 50", "20 to 50", "5 to 20", "Top 5%")
qq <- quantile(x, probs = c(0, 0.50, 0.70, 0.95, 1))

idx <- findInterval(x, qq)
val[idx]


Hope this helps,

Rui Barradas

Em 31-07-2013 10:37, Dark escreveu:
> Hi all,
>
> I think this should be an easy question for the guru's out here.
>
> I have this large data frame (2.500.000 rows, 15 columns) and I want to add
> a column named "SEGMENT" to it.
> The first 5% rows (first 125.000 rows) should have the value "Top 5%" in the
> SEGMENT column
> Then the rows from 5% to 20% should have the value "5 to 20"
> Then 20-50% should have the value "20 to 50"
> And the last 50% of the rows should have the value "Bottom 50"
>
> What is the easiest way of doing this? I was thinking of using quantile but
> then I should have some rownumber column.
>
> Regards Derk
>
>
>
> --
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