I have a dataframe with multiple variables and I would like to find the quantiles () of each of these variables
Sample code:
testtable = data.frame(groupvar = c(rep('x',100), rep('y',100)),
numericvar = rnorm(200))
I want to apply quantile(., c(.05, .1, .25, .5, .75, .9, .95)) to each of the variables in testtable. The ideal result would look like
x y
.05 .05
.1 .1
.25 .25
.5 .5
.75 .75
.9 .9
.95 .95
where each entry is a quantile of x or y. For sample, .05 is the 5th percentile of the x .1 is the 10th percentile distribution of x, etc.
I tried summarise in dplyr but ran into a problem because my quantile function is returning a vector of length 7.
What is the best way to do this?
Here is a base R solution where we unstack the data frame and calculating the quantile for each column, for each quantile, i.e.
sapply(unstack(testtable, numericvar ~ groupvar), function(i) quantile(i, v1))
which gives,
x y 5% -1.82980882 -1.49900735 10% -1.26047295 -1.02626933 25% -0.83928910 -0.68248217 50% 0.02757385 -0.02096953 75% 0.64842517 0.48624513 90% 1.63382801 1.09722178 95% 1.91104161 1.72846846
where v1 <- c(0.05, 0.1, 0.25, 0.5, 0.75, 0.9, 0.95)