Is there a R function to make bins for barplots?

Question

I am trying to make 41 bins for a variable.

suppose this is the variable for 2014

d<-runif(10300, -4.740, 6.142)
d<-as.data.frame(d)

Now what I want is to know the range for each bin

So the first bin should be like

min(d$d) -< min(d$d)+(max(d$d)-min(d$d))/41-1

and so on... till you get the 41 bins.

I was doing this, but is taking way too long.

bins<-seq(min(d$d), max(d$d), by=(max(d$d)-min(d$d))/41-1`)

d$bins<- ifelse(d$d<bins[2], paste(bins[1], bins[2], sep="-<"),
               ifelse(d$d<=bins[2] & d$d <bins[3], paste(bins[2], bins[3], sep="-",
                      another nested ifelse)))

And so on, but is taking a lot of time

So in the dataframe d i'd like to have:

• one column that tells you the number of the bin (1-41)
• one column that tells you the range of the bin (i.e. "-4.740 -< -4.470")

Is there a function to do that or a faster way to do it?

Thanks in advance!

---

what i am trying to do with this is to make a barplot in ggplot that on the x axis are the bin ranges and in Y a count of how many obs. there are within that bin.

Answer 1

Another version using my santoku package:

library(santoku)
d$bin <- chop_evenly(d$d, 41)
d$bin_num <- as.numeric(d$bin)

Answer 2

You can use cut and specify the number of breaks that you want.

library(dplyr)
library(ggplot2)

d %>%
  mutate(bin_range = cut(d, 41), 
         bin_num = as.numeric(bin_range)) %>% head

#           d       bin_range bin_num
#1  0.8337735     (0.834,1.1]      22
#2 -3.2143150   (-3.41,-3.15]       6
#3  3.2491203     (3.22,3.49]      31
#4 -3.7117195   (-3.94,-3.68]       4
#5 -0.4843214 (-0.493,-0.228]      17
#6 -4.0540989   (-4.21,-3.94]       3

To plot, you can use ggplot2

d %>%
  mutate(bin_range = cut(d, 41), 
         bin_num = as.numeric(bin_range)) %>% 
  count(bin_range) %>%
  ggplot(aes(bin_range, n)) + 
  geom_col()  +
  theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))