Compute percentile for a given value

Question

In a dataframe I have a column with the total score on a questionnaire. I want to add a column in which, for each total score, there is the relative percentile with respect to the data distribution. How can I do it in R?

Answer 1

Let x be the data.frame, and let x$score be the column of the total score. You could add a column of percentile by

x$percentile <- ecdf(x$score)(x$score)

Now the data.frame x has an additional column percentile, which is what you want.