如何通過在dplyr

Question

列索引組我遇到的情況，我在一個變量得到列索引和我有GROUP BY和變量

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

> col_index 
    X__7 
    8 

現在我的希望將總結col_index值如下

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

它給我下面的錯誤。

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

col_index具有動態值。我該怎麼做r？

Answer 1

您可以通過搭配使用group_by_if給定函數的所有列組：

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

Answer 2

嘗試以下操作：

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：我不得不使用colnames在sapply得到它在我的機器上正確工作

圖片來源：我接受了dplyr: how to reference columns by column index rather than column name using mutate?