在GROUP_BY之前删除NAS并在用户定义的函数中汇总

模拟数据:

df = structure(list(country = c("USA", "USA", "Japan", NA), dimension = c("economic", 
"cultural", "economic", "economic"), score = c(NA, "high", "high", 
"low")), class = "data.frame", row.names = c(NA, -4L))

我编写了这个函数来汇总每个变量的频率，然后将它们导出为CSV，文件名为该变量的名称:

export <- function(df){   
  for (col in colnames(df)) {  
    table <- df %>%
      group_by(df[col]) %>%
      summarise(Count = n()) %>% 
      mutate(Percent = Count / sum(Count)*100,
             N = sum(Count))
    write.csv(table, paste0(col, ".csv"), row.names = F)
    print(table)
  }                            
}             

export(df) --> this works

但我想在分组数据和计算频率之前删除NA.我这样做了:

export <- function(df){   
  for (col in colnames(df)) {  
    table <- df %>%
      filter(!is.na(df[col])) %>%  # Attempt to filter out NAs
      group_by(df[col]) %>%
      summarise(Count = n()) %>% 
      mutate(Percent = Count / sum(Count)*100,
             N = sum(Count))
    write.csv(table, paste0(col, ".csv"), row.names = F)
    print(table)
  }                            
}  

export(df) --> this does not work, and I get this error message:

Error in `group_by()`:
ℹ In argument: `df[col]`.
Caused by error:
! `df[col]` must be size 3 or 1, not 4.

如何删除这些Nas？？我一定是犯了个愚蠢的错误.

当前输出(只显示要迭代的三个变量中的第一个):

country Count   Percent N
Japan   1       25      4
USA     2       50      4
NA      1       25      4

所需的输出(只显示了要迭代的三个变量中的第一个):

country Count   Percent     N
Japan   1       33.33333    3
USA     2       66.66667    3

注意，NA被丢弃并且不包括在频率中.