重新排序的列名

Question

可能重複：
How to sort a dataframe by column(s) in R

這裏是數據集：

odervect <- c("xaf", "c3a", "c3b", "ka101","jk12", "cd101", "kl01v", "klm1") 
odervect 
[1] "xaf" "c3a" "c3b" "ka101" "jk12" "cd101" "kl01v" "klm1" 

dfd <- data.frame(ka101 = 101:110,c3a = 1:10, kl01v = 301:310, xaf = 11:20, 
    c3b = 41:50, cd101 = 61:70) 


dfd 

    ka101 c3a kl01v xaf c3b cd101 
1 101 1 301 11 41 61 
2 102 2 302 12 42 62 
3 103 3 303 13 43 63 
4 104 4 304 14 44 64 
5 105 5 305 15 45 65 
6 106 6 306 16 46 66 
7 107 7 307 17 47 67 
8 108 8 308 18 48 68 
9 109 9 309 19 49 69 
10 110 10 310 20 50 70 

希望的輸出：

dfd1 <- data.frame(xaf = 11:20, c3a = 1:10, c3b = 41:50,ka101 = 101:110, cd101 = 61:70, 
    ka101v = 301:310) 
    dfd1 
     xaf c3a c3b ka101 cd101 ka101v 
1 11 1 41 101 61 301 
2 12 2 42 102 62 302 
3 13 3 43 103 63 303 
4 14 4 44 104 64 304 
5 15 5 45 105 65 305 
6 16 6 46 106 66 306 
7 17 7 47 107 67 307 
8 18 8 48 108 68 308 
9 19 9 49 109 69 309 
10 20 10 50 110 70 310 

請注意，並非所有名字順序矢量都存在於dfd中，但只需要對匹配的名稱進行排序。

Answer 1

這個怎麼樣？它首先使用%in%選擇（仍然按順序）在odervect對應於列名dfd目前字符串：

cnames <- odervect[odervect %in% names(dfd)] 
dfd[cnames] 
    xaf c3a c3b ka101 cd101 kl01v 
1 11 1 41 101 61 301 
2 12 2 42 102 62 302 
3 13 3 43 103 63 303 
4 14 4 44 104 64 304 
5 15 5 45 105 65 305 
6 16 6 46 106 66 306 
7 17 7 47 107 67 307 
8 18 8 48 108 68 308 
9 19 9 49 109 69 309 
10 20 10 50 110 70 310