Question

这是我的数据

> a
 [1] Male   Male   Female Male   Male   Male   Female Female Male   Male   Female Male   Male   Male  
[15] Female Female Female Male   Female Male   Female Male   Male   Female Male   Male   Female Male  
[29] Male   Male   Female Male   Male   Male   Female Female Male   Male   Male   Male   Male  
Levels:  Female Male

> b
[1] 0 1 0 1 0 0 0 0 1 1 1 1 0 1 0 0 0 1 0 0 1 0 0 0 1 1 1 0 0 0 0 1 1 0 0 1 0 1 1 1 1
Levels: 0 1

> table(a,b)
        b
a         0  1
          0  0
  Female 10  4
  Male   12 15

我不知道为什么table(a,b)的结果有一行(0 0)，我的预期结果如下：

> table(a,b)
        b
a         0  1
  Female 10  4
  Male   12 15

你能告诉我为什么会这样，以及如何纠正它，谢谢！

> dput(a)
structure(c(3L, 3L, 2L, 3L, 3L, 3L, 2L, 2L, 3L, 3L, 2L, 3L, 3L, 
3L, 2L, 2L, 2L, 3L, 2L, 3L, 2L, 3L, 3L, 2L, 3L, 3L, 2L, 3L, 3L, 
3L, 2L, 3L, 3L, 3L, 2L, 2L, 3L, 3L, 3L, 3L, 3L), .Label = c("", 
"Female", "Male"), class = "factor")

> dput(b)
structure(c(1L, 2L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 1L, 
2L, 1L, 1L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 1L, 2L, 2L, 2L, 1L, 1L, 
1L, 1L, 2L, 2L, 1L, 1L, 2L, 1L, 2L, 2L, 2L, 2L), .Label = c("0", 
"1"), class = "factor")

Answer 1

来自上述评论：

这种情况正在发生，因为a中有一个空因子级别：

> levels(a)
[1] ""       "Female" "Male"

你可以继续制作一张无法考虑空因子水平的表格（来自@ lmo的评论）：

table(as.character(a), b)

或者，您可以轻松删除因素级别而无需观察（来自@ Dave2e的评论）

a <- droplevels(a)
table(a, b)

计算R中的频率

1 个答案: