Binning a numeric variable in R

Question

I have a vector X that contains positive numbers that I want to bin/discretize. For this vector, I want the numbers [0, 10) to show up just as they exist in the vector, but numbers [10,∞) to be 10+.

I'm using:

x <- c(0,1,3,4,2,4,2,5,43,432,34,2,34,2,342,3,4,2)
binned.x <- as.factor(ifelse(x > 10,"10+",x))

but this feels klugey to me. Does anyone know a better solution or a different approach?

Answer 1

How about cut:

binned.x <- cut(x, breaks = c(-1:9, Inf), labels = c(as.character(0:9), '10+'))

Which yields:

 # [1] 0   1   3   4   2   4   2   5   10+ 10+ 10+ 2   10+ 2   10+ 3   4   2  
 # Levels: 0 1 2 3 4 5 6 7 8 9 10+

Answer 2

You question is inconsistent.
In description 10 belongs to "10+" group, but in code 10 is separated level. If 10 should be in the "10+" group then you code should be

as.factor(ifelse(x >= 10,"10+",x))

In this case you could truncate data to 10 (if you don't want a factor):

pmin(x, 10)
# [1]  0  1  3  4  2  4  2  5 10 10 10  2 10  2 10  3  4  2 10

Answer 3

x[x>=10]<-"10+"

This will give you a vector of strings. You can use as.numeric(x) to convert back to numbers ("10+" become NA), or as.factor(x) to get your result above.

Note that this will modify the original vector itself, so you may want to copy to another vector and work on that.