根据R中的目标向量对数据帧组进行排序

Question

I have a dataframe such as shown below (original data is really big). I want to sort them based on the group of target vector and get the result.

dataframe

sample     group    
A           AA 
B           CC
C           CC
D           BB
E           AA
F           AA

target.vector <- c("AA", "BB", "CC")

result

 sample     group    
    A           AA 
    E           AA
    F           AA
    D           BB
    B           CC
    C           CC

Answer 1

You could turn group into a factor and then use order eg for your sample data

...
df$group <- factor(df$group, levels=c('AA', 'CC', 'BB'))
df[order(df$group), ]

would result in

  sample group
1      A    AA
5      E    AA
6      F    AA
2      B    CC
3      C    CC
4      D    BB

Answer 2

We can use data.table . Convert the 'data.frame' to 'data.table', set the key as 'group' and join with the 'target.vector'

library(data.table)
setDT(df1, key = "group")[target.vector]
#     sample group
#1:      A    AA
#2:      E    AA
#3:      F    AA
#4:      D    BB
#5:      B    CC
#6:      C    CC

Changing the 'target.vector' does change the order

target.vector <- c("BB", "AA", "CC")
setDT(df1, key = "group")[target.vector]
#   sample group
#1:      D    BB
#2:      A    AA
#3:      E    AA
#4:      F    AA
#5:      B    CC
#6:      C    CC

---

Or a base R option would be match

df1[with(df1, order(match(group, target.vector))),]
#   sample group
#1      A    AA
#2      E    AA
#3      F    AA
#4      D    BB
#5      B    CC
#6      C    CC