如列表命名为 raw.data
summary(as.factor(raw.data$subject))
就可以了。举一个列子:
a<-c("a","a","b","c")
summary(as.factor(a))
建议你选择subset函数subset函数,从某一个数据框中选择出符合某条件的数据或是相关的列
(1)单条件查询
>selectresult=subset(df1,name=="aa")
>selectresult
name age sex
1 aa 20 f
>df1
name age sex
1 aa 20 f
2 bb 29 m
3 cc 30 f
(2)指定显示列
>selectresult=subset(df1,name=="aa",select=c(age,sex))
>selectresult
age sex
1 20 f
(3)多条件查询
>selectresult=subset(df1,name=="aa" &sex=="f",select=c(age,sex))
>selectresult
age sex
1 20 f
>df1
name age sex
1 aa 20 f
2 bb 29 m
3 cc 30 f