Dplyr管道操作获得最低要求

由 non_at发布于 2020-05-09 06:20:21

当尝试将R管道操作与获得最小值组合在一起时，我遇到了这个问题。我希望这能奏效，但不能奏效。谁能向我解释为什么会这样，以及如何解决？

df <- data.frame(ID = c(1,2,3,4),
                 Name = c("Name1", "Name1", "Name2", "Name3"),
                 Value = c(10, 14, 13, 1))

df <- df %>%
        filter(grepl("name1", Name, ignore.case = TRUE)) %>%
        min(Value) 

Error in function_list[[k]](value) : object 'Value' not found

没文化

2020-05-09 06:20:21

We can pull the column 'Value' as a vector and get the min

library(dplyr)
df %>%
       filter(grepl("name1", Name, ignore.case = TRUE)) %>% 
       pull(Value) %>% 
       min

Or use summarise

 df %>%
       filter(grepl("name1", Name, ignore.case = TRUE)) %>%
       summarise(Value = min(Value))

The reason is that the output from the %>% is the full dataset, we need to extract the column with $ or [[

df %>%
    filter(grepl("name1", Name, ignore.case = TRUE)) %>%
     {min(.$Value)}
#[1] 10

non_at

这家伙很懒，什么都没留下

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