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我试图通过传递一个变量列表以首先按升序使用,一个变量按降序(最后按排列顺序)来动态排列数据帧。每次迭代都选择顶行并存储另一个数据框。下面的示例仅在传递单个降序变量时有效,但我无法使其与变量列表一起使用。

top_n_order <- function(df,n, expr_var, ... ){

  expr_var <- enquo(expr_var)
  dots <- list(...)
  expr_order <- enquos(...)

  if (!is_empty(dots)){
    arrange_call <- lazyeval::interp(~ list(x,desc(y)), x=expr_order, y=expr_var)

    selected_df <- df %>%
      arrange_(.dots = list(arrange_call)) %>%
      rownames_to_column("model_name") %>%
      select(mpg, cyl,  !! expr_var) %>%
      head(n)
    selected_df
  }else{
    selected_df <- df %>% 
      arrange(desc(!! expr_var)) %>%
      rownames_to_column("model_name") %>%
      select(model_name, mpg,cyl,  !! expr_var) %>%
      head(n)
    selected_df
  }

}

v_cols <- colnames(mtcars) 
cars_top_df <- data.frame()

top_n_order(mtcars, 5, as.name(v_cols[3]) )  ##Works


for(i in 1:length(v_cols)){
  v_order <- lapply(as.list(v_cols[-i]), as.name)
  tmp_selected <- top_n_order(mtcars, 5, as.name(v_cols[i]), v_order )  
  cars_top_df <- bind_rows(cars_top_df,tmp_selected)
}
cars_top_df %>%
  arrange(model_name)

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