Question

我有一个场景，我在变量中得到列索引，我必须分组并按该变量汇总

 col_index <- which(sapply(dataframe, function(x) any(x == "Area of Maintenance")))

> col_index
  X__7 
  8

现在我想按col_index分组，如下面的

df%>%
group_by(df[col_index]) %>%
summarise(count = n()) %>%
as.data.frame()

它给了我以下错误。

Error in mutate_impl(.data, dots) : 
Evaluation error: Column index must be at most 1 if positive, not 8.

col_index具有动态值。我怎么能在r？

中做到这一点

Answer 1

您可以使用group_by_if

按照与给定函数匹配的所有列进行分组

df %>%
    group_by_if(function(x) any(x == "Area of Maintenance")) %>%
    summarise(count = n()) %>%
    as.data.frame()

Answer 2

尝试以下方法：

col_index <- which(sapply(colnames(dataframe), function(x) any(x == "Area of Maintenance")))

df%>%
group_by(.[[col_index]]) %>%
summarise(count = n()) %>%
as.data.frame()

注意：我必须在colnames中使用sapply才能让它在我的机器上正常工作

信用：我从dplyr: how to reference columns by column index rather than column name using mutate?

获得了帮助

如何在dplyr中对列索引进行分组

2 个答案: