How to create simple summary statistics using dplyr from multiple variables? Using the summarise_each function seems to be the way to go, however, when applying multiple functions to multiple columns, the result is a wide, hard-to-read data frame.
Use dplyr in combination with tidyr to reshape the end result.
library(dplyr)
library(tidyr)
df <- tbl_df(mtcars)
df.sum <- df %>%
select(mpg, cyl, vs, am, gear, carb) %>% # select variables to summarise
summarise_each(funs(min = min,
q25 = quantile(., 0.25),
median = median,
q75 = quantile(., 0.75),
max = max,
mean = mean,
sd = sd))
# the result is a wide data frame
> dim(df.sum)
[1] 1 42
# reshape it using tidyr functions
df.stats.tidy <- df.sum %>% gather(stat, val) %>%
separate(stat, into = c("var", "stat"), sep = "_") %>%
spread(stat, val) %>%
select(var, min, q25, median, q75, max, mean, sd) # reorder columns
> print(df.stats.tidy)
var min q25 median q75 max mean sd
1 am 0.0 0.000 0.0 1.0 1.0 0.40625 0.4989909
2 carb 1.0 2.000 2.0 4.0 8.0 2.81250 1.6152000
3 cyl 4.0 4.000 6.0 8.0 8.0 6.18750 1.7859216
4 gear 3.0 3.000 4.0 4.0 5.0 3.68750 0.7378041
5 mpg 10.4 15.425 19.2 22.8 33.9 20.09062 6.0269481
6 vs 0.0 0.000 0.0 1.0 1.0 0.43750 0.5040161