如何选择包含R中所选行的特定值的列？

我有一个像这样的数据集

Site <- c(1,2,3,4,5,6,7,8,9,10,"kingdom","phylum","class")
A <- c(0,0,1,2,4,5,6,7,13,56,"Eukaryota","Arthropoda","Insecta")
B <- c(1,0,0,0,0,4,5,7,7,8,"Eukaryota","Arthropoda","Insecta")
C <- c(2,3,0,0,4,5,67,8,43,21,"Eukaryota","Arthropoda","")
D <- c(134,0,0,2,0,0,9,0,45,55,"Eukaryota","Arthropoda","Arachnida")
site.species.sample <- data.frame(Site,A,B,C,D)

那我该怎么做呢？谢谢

下面是一个选项

site.species.sample[,c(TRUE,subset(site.species.sample[,-1],site.species.sample$Site=="class")=="Insecta")]

Site          A          B
1        1          0          1
2        2          0          0
3        3          1          0
4        4          2          0
5        5          4          0
6        6          5          4
7        7          6          5
8        8          7          7
9        9         13          7
10      10         56          8
11 kingdom  Eukaryota  Eukaryota
12  phylum Arthropoda Arthropoda
13   class    Insecta    Insecta

---

有没有理由将字符和数字数据放在同一列中？是的，这就是我的数据集的格式我可以问一下[，-1]是什么意思吗？ThanksIt从子集中排除第一列，以确保在任何情况下都会选择它。然后使用cTRUE，插入TRUE作为向量的第一个元素来选择第一列。你们知道为什么我的原始代码不起作用吗？这个命令怎么了？Thankssite.species.sample[class]，此部分给出错误，因为没有名为class的列

Error in `[.data.frame`(site.species.sample, , site.species.sample["class",  : 
undefined columns selected

site.species.sample[,c(TRUE,subset(site.species.sample[,-1],site.species.sample$Site=="class")=="Insecta")]

Site          A          B
1        1          0          1
2        2          0          0
3        3          1          0
4        4          2          0
5        5          4          0
6        6          5          4
7        7          6          5
8        8          7          7
9        9         13          7
10      10         56          8
11 kingdom  Eukaryota  Eukaryota
12  phylum Arthropoda Arthropoda
13   class    Insecta    Insecta