我想知道如何从R中的表中获取特定行。例如,
> a <- c(13,13,
14,14,14,14,14,14,
15,15,15,15,15,15,
16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
17,17,17,17,17,17,17,
18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,
19,19,19,19,19,19,19,19,19,19,19,
20,20,20,20,20,20,20,20,20,
21,21,21,21,21,21,21,21,21,21,21,
22,22,22,22,22,22,22,22,22,
23,23,23,24,25,25,27)
> table(a)
a
13 14 15 16 17 18 19 20 21 22 23 24 25 27
2 6 6 15 7 17 11 9 11 9 3 1 2 1
如何提取表格的最后一行?
答案 0 :(得分:39)
函数str()
允许您查询对象的结构
str(table(a))
# 'table' int [1:14(1d)] 2 6 6 15 7 17 11 9 11 9 ...
# - attr(*, "dimnames")=List of 1
# ..$ a: chr [1:14] "13" "14" "15" "16" ...
您的表对象类似于向量(它只有一些额外的标记/属性)。至关重要的是,您可以通常的方式访问元素:
R> b = table(a)
##To get the numerical values
R> as.vector(b)
[1] 2 6 6 15 7 17 11 9 11 9 3 1 2 1
##To get the names
R> names(b)
[1] "13" "14" "15" "16" "17" "18" "19" "20" "21" "22" "23" "24" "25" "27"
另外,我们可以使用标准子设置规则
##Get the last element in the named vector
R> b[length(b)]
27
1
R> names(b)[length(b)]
[1] "27"