问题
I have a data frame which looks like this :
a = c("1A","10A","11A","2B","2C","22C","3A","3B")
b= c(1,2,3,4,5,6,7,8)
ab = data.frame(a,b)
and I want to sort it according to the column a. I tried the mixed order
library(gtools)
ab[mixedorder(ab$a),]
but I don' t get the result I want (1A,2B,2C,3A,3B..). How can I fix this?
回答1:
We need to convert to character class (as the 'a' column is factor based on the default option in data.frame call i.e. stringsAsFactors=TRUE)
ab[mixedorder(as.character(ab$a)),]
# a b
#1 1A 1
#4 2B 4
#5 2C 5
#7 3A 7
#8 3B 8
#2 10A 2
#3 11A 3
#6 22C 6
Additional options are also explained in here
回答2:
I'd just split the column. If you want numeric order for the numbers part of the ID, you should probably have these numbers as a numeric column anyway.
ab$a1 <- as.numeric(gsub("[[:alpha:]+]", "", ab$a))
ab$a2 <- gsub("\\d+", "", ab$a)
ab[order(ab$a1, ab$a2),]
# a b a1 a2
#1 1A 1 1 A
#4 2B 4 2 B
#5 2C 5 2 C
#7 3A 7 3 A
#8 3B 8 3 B
#2 10A 2 10 A
#3 11A 3 11 A
#6 22C 6 22 C
来源：https://stackoverflow.com/questions/39270292/mixedorder-data-frame-in-r