我的数据框如下所示。
`> am_me
Group.1 Group.2 x.x x.y
2 AM clearterminate 3 21.00000
3 AM display.cryptic 86 30.12791
4 AM price 71 898.00000`
我想得到如下结果。
`> am_me_t
Group.2 x.x x.y
2 clearterminate 3 21
3 display.cryptic 86 30.1279069767442
4 price 71 898
41 AM 160 316.375968992248`
我已取出第一列并得到如下结果
`> am_res
Group.2 x.x x.y
2 clearterminate 3 21.00000
3 display.cryptic 86 30.12791
4 price 71 898.00000`
当我尝试rbind将“AM”添加到新行时，如下所示，我收到一条警告消息并获得NA。
`> am_me_t <- rbind(am_res, c("AM", colSums(am_res[2]), colMeans(am_res[3])))
Warning message:
invalid factor level, NAs generated in: "[<-.factor"(`*tmp*`, ri, value = "AM")
Group.2 x.x x.y
2 clearterminate 3 21
3 display.cryptic 86 30.1279069767442
4 price 71 898
41 <NA> 160 316.375968992248`
有关您的信息，请输出编辑（am_me）
`> edit(am_me)
structure(list(Group.1 = structure(as.integer(c(2, 2, 2)), .Label = c("1Y",
"AM", "BE", "CM", "CO", "LX", "SN", "US", "VK", "VS"), class = "factor"),
Group.2 = structure(as.integer(c(2, 5, 9)), .Label = c("bestbuy",
"clearterminate", "currency.display", "display", "display.cryptic",
"fqa", "mileage.display", "ping", "price", "reissue", "reissuedisplay",
"shortaccess.followon"), class = "factor"), x.x = as.integer(c(3,
86, 71)), x.y = c(21, 30.1279069767442, 898)), .Names = c("Group.1",
"Group.2", "x.x", "x.y"), row.names = c("2", "3", "4"), class = "data.frame")`
另外
`> edit(me)
structure(list(Group.1 = structure(as.integer(c(1, 2, 2, 2, 3,
4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 8, 8,
8, 8, 9, 9, 10, 10, 10, 10, 10, 10)), .Label = c("1Y", "AM",
"BE", "CM", "CO", "LX", "SN", "US", "VK", "VS"), class = "factor"),
Group.2 = structure(as.integer(c(8, 2, 5, 9, 10, 1, 2, 5,
9, 1, 2, 5, 9, 1, 2, 3, 4, 7, 9, 11, 12, 2, 4, 6, 1, 2, 5,
9, 2, 5, 1, 2, 3, 5, 9, 10)), .Label = c("bestbuy", "clearterminate",
"currency.display", "display", "display.cryptic", "fqa",
"mileage.display", "ping", "price", "reissue", "reissuedisplay",
"shortaccess.followon"), class = "factor"), x.x = as.integer(c(1,
3, 86, 71, 1, 2, 5, 1, 52, 10, 7, 27, 15, 5, 267, 14, 4,
1, 256, 1, 1, 80, 1, 78, 2, 10, 23, 6, 1, 2, 4, 3, 3, 11,
1, 1)), x.y = c(5, 21, 30.1279069767442, 898, 12280, 800,
56.4, 104, 490.442307692308, 1759.1, 18.1428571428571, 1244.81481481481,
518.533333333333, 3033.2, 18.5468164794007, 20, 3788.5, 23,
2053.49609375, 3863, 6376, 17.825, 240, 1752.21794871795,
1114.5, 34, 1369.60869565217, 1062.16666666667, 23, 245,
5681.5, 11.3333333333333, 13.3333333333333, 1273.81818181818,
2076, 5724)), .Names = c("Group.1", "Group.2", "x.x", "x.y"
), row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "9",
"10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
"21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31",
"32", "33", "34", "35", "36"), class = "data.frame")
Group.1 Group.2 x.x x.y
1 1Y ping 1 5.00000
2 AM clearterminate 3 21.00000
3 AM display.cryptic 86 30.12791
4 AM price 71 898.00000
5 BE reissue 1 12280.00000
6 CM bestbuy 2 800.00000
7 CM clearterminate 5 56.40000
8 CM display.cryptic 1 104.00000
9 CM price 52 490.44231
10 CO bestbuy 10 1759.10000
11 CO clearterminate 7 18.14286
12 CO display.cryptic 27 1244.81481
13 CO price 15 518.53333
14 LX bestbuy 5 3033.20000
15 LX clearterminate 267 18.54682
16 LX currency.display 14 20.00000
17 LX display 4 3788.50000
18 LX mileage.display 1 23.00000
19 LX price 256 2053.49609
20 LX reissuedisplay 1 3863.00000
21 LX shortaccess.followon 1 6376.00000
22 SN clearterminate 80 17.82500
23 SN display 1 240.00000
24 SN fqa 78 1752.21795
25 US bestbuy 2 1114.50000
26 US clearterminate 10 34.00000
27 US display.cryptic 23 1369.60870
28 US price 6 1062.16667
29 VK clearterminate 1 23.00000
30 VK display.cryptic 2 245.00000
31 VS bestbuy 4 5681.50000
32 VS clearterminate 3 11.33333
33 VS currency.display 3 13.33333
34 VS display.cryptic 11 1273.81818
35 VS price 1 2076.00000
36 VS reissue 1 5724.00000`
答案 0 :(得分：3)
Group.2列的类型是factor，它限制了可能的值。您可以使用am_me$Group.2 <- as.character(am_me$Group.2)将其转换为字符，之后将添加AM值而不会出错。
请注意，您还可以使用sum()和mean()进行单列操作。