如何停止在 dplyr 中使用 rowwise? [英] How does one stop using rowwise in dplyr?

问题描述

因此，如果希望在 dplyr 中逐行应用操作，可以使用 rowwise 函数，例如:使用 dplyr 将函数应用于表的每一行?

So, if one wishes to apply an operation row by row in dplyr, one can use the rowwise function, for example: Applying a function to every row of a table using dplyr?

是否有一个 unrowwise 函数可以用来逐行停止操作?目前，似乎在 rowwise 删除行操作之后添加了一个 group_by，例如

Is there a unrowwise function which you can use to stop doing operations row by row? Currently, it seems adding a group_by after the rowwise removes row operations, e.g.

data.frame(a=1:4) %>% rowwise() %>% group_by(a)
# ...
# Warning message:
# Grouping rowwise data frame strips rowwise nature 

这是否意味着如果您希望显式删除 rowwise，应该使用 group_by(1)?

Does this mean one should use group_by(1) if you wish to explicitly remove rowwise?

推荐答案

正如在评论和其他答案中发现的那样，正确的做法是使用 ungroup().

As found in the comments and the other answer, the correct way of doing this is to use ungroup().

操作rowwise(df) 将df 的类之一设置为rowwise_df.通过检查代码here，给出以下ungroup方法:

The operation rowwise(df) sets one of the classes of df to be rowwise_df. We can see the methods on this class by examining the code here, which gives the following ungroup method:

#' @export
ungroup.rowwise_df <- function(x) {
  class(x) <- c( "tbl_df", "data.frame")
  x
}

所以我们看到ungroup 并没有严格删除分组结构，而是删除了从rowwise 函数中添加的rowwise_df 类.

So we see that ungroup is not strictly removing a grouped structure, instead it just removes the rowwise_df class added from the rowwise function.

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