adam.888 adam.888 - 2 months ago 10
R Question

R:cut extracting the minimum and maximum of cut levels as columns in data.frame

I have a numeric vector that I want to convert to five numeric levels.
I can get the five levels using cut

dx <- data.frame(x=1:100)
dx$cut <- cut(dx$x,5)


But I am now having problems extracting the lower and upper boundaries of the levels.
So for example
(0.901,20.8] would be 0.901 in dx$min and 20.8 in dx$max.

I tried:

dx$min <- pmin(dx$cut)
dx$max <- pmax(dx$cut)
dx


But this does not work.
Thank you for any help.

Answer

you can try splitting the labels (converted to character beforehand and modified to suppress the punctuation except , and .) according to the comma and then create 2 columns:

min_max <- unlist(strsplit(gsub("(?![,.])[[:punct:]]", "", as.character(dx$cut), perl=TRUE), ",")) # here, the regex ask to replace every punctuation mark except a . or a , by an empty string

dx$min <- min_max[seq(1, length(min_max), by=2)]
dx$max <- min_max[seq(2, length(min_max), by=2)]

head(dx)
#  x          cut   min  max
#1 1 (0.901,20.8] 0.901 20.8
#2 2 (0.901,20.8] 0.901 20.8
#3 3 (0.901,20.8] 0.901 20.8
#4 4 (0.901,20.8] 0.901 20.8
#5 5 (0.901,20.8] 0.901 20.8
#6 6 (0.901,20.8] 0.901 20.8
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