R - Count the number of observations in intervals-CodePudding

I want to have make intervals and to count the number of observations pro interval.

Then, I want to count the number of observations with a condition (here, the number of cars which have 3 or 4 gears) pro interval.

For now, I did something like this:

data(mtcars)

tb1 = table(
  cut(mtcars$mpg,
      breaks = seq.int(from = min(mtcars$mpg), to = max(mtcars$mpg) 1, by = 5))) %>%
  as.data.frame()

But I have trouble constructing my intervals and I do not know how to say that I want to count the number of observations with a condition.

I would finally like something like this:

   intervals   obs   gear_3   gear_4
   [10,15)      5      5        0
   [15, 20)     13     8        2
   [20, 25)     8      2        6
   [25, 30)     2      0        1
   [30, 35)     4      0        3

CodePudding user response：

Something like this?

library(dplyr)


mtcars %>%
  mutate(bin = as.numeric(cut(mpg, seq(min(mpg), max(mpg), 5)))) %>%
  count(cyl, bin)
#>   cyl bin n
#> 1   4   3 5
#> 2   4   4 4
#> 3   4  NA 2
#> 4   6   2 4
#> 5   6   3 3
#> 6   8   1 6
#> 7   8   2 6
#> 8   8  NA 2