如何在R中的表输出中对因子级别进行排序？

Question

Suppose I have two binary variables:

group <- rbinom(100,1,0.6)
y <- rbinom(100,1,0.3)

table(group,y)
         y
    group  0  1
        0 26 13
        1 42 19

How to table out or sort the table output in this format:

     y
group  1  0
    0 13 26
    1 19 42

Answer 1

Depending on what bigger problem you are trying to solve, either one of these approaches might be helpful. For reference, here is what I get initially:

> set.seed(1)
> group<-rbinom(100,1,0.6)
> y<-rbinom(100,1,0.3)
> 
> table(group,y)
     y
group  0  1
    0 28 15
    1 42 15

You can redefine y to be a factor with your own choice of ordering of the factor levels and then tabulate:

> table(group,factor(y,levels=c("1","0")))

group  1  0
    0 15 28
    1 15 42

Or you can run the table as above and then sort the columns of the output:

> table(group,y)[,c("1","0")]
     y
group  1  0
    0 15 28
    1 15 42