Creating an equal depth bin

Hi all,

I have a task where I am creating an equal depth bin. My goal is to come up with the following bin:

[3, 4), [5, 6] and [7, 8]
quality <- c(3, 4, 5, 6, 7, 8) <- data.frame(quality)
w <- classIntervals($quality
                    , n=3
                    , style = "pretty"

But when I run my R code I get this

[2,4) [4,6) [6,8]

I request someone to point me in the right direction.

Thank you,


Can you supply us with your code and some sample data.

For some suggestions see:

1 Like

Hi Ron,

What you get is correct, it seems to me. R treats your vector as a numeric, so a continuous interval ranging from 3 to 8. The binning therefore is continuous. R returns is the interval splits, not where the elements of your vector go. Are you probably looking for following explanation (I used cut-function, not your package)?

# [1] "numeric"                                                               
cut(quality, breaks = c(3,4,6,8), include.lowest = TRUE)                      
# [1] [3,4] [3,4] (4,6] (4,6] (6,8] (6,8]                                     
# Levels: [3,4] (4,6] (6,8]                                                   
table(cut(quality, breaks = c(3,4,6,8), include.lowest = TRUE) )              
# [3,4] (4,6] (6,8]                                                           
#     2     2     2                                                           
#use split to see the element-split                                           
f  <- as.factor(cut(quality, breaks = c(3,4,6,8), include.lowest = TRUE) )    
split(quality, f)                                                             
# $`[3,4]`                                                                    
# [1] 3 4                                                                     
# $`(4,6]`                                                                    
# [1] 5 6                                                                     
# $`(6,8]`                                                                    
# [1] 7 8                                                                     

Otherwise, as @jrkrideau suggests, you need to provide more information for what you trying to achieve.

Hope this helps, JW

1 Like

Hi JW,

Thanks for the information. I will definitely do what JW suggested next time I ask a question.

The cut package does a better a job in making me understand what I was trying to achieve.

Thank you,


Hi Ron,

Glad to be of help. Note that cut is not a package, but a base R function, so always available! If you are looking to understand what is going on, looking into base R solutions for common operations, would be my general recommendation. Gives a feeling what is going on under the hood.

Welcome and have fun withR!


This topic was automatically closed 21 days after the last reply. New replies are no longer allowed.

If you have a query related to it or one of the replies, start a new topic and refer back with a link.