r - 如何在没有 gtsummary 包的情况下为分类变量创建频率表

Question

gender <- c("male","female","female","male",NA)
test_resurt <- c("positive","negative",NA,"positive","negative")
homeless <- factor(c("yes","no","yes","no","no"))
df <- as.data.frame(cbind(gender,test_resurt,homeless))
df
#>   gender test_resurt homeless
#> 1   male    positive        2
#> 2 female    negative        1
#> 3 female        <NA>        2
#> 4   male    positive        1
#> 5   <NA>    negative        1

library(gtsummary)
tbl <-tbl_summary(df)

输出

如何在不使用 gtsummary 包的情况下制作汇总表？