如何将摘要输出转换为数据框？ [英] How to convert summary output to a data frame?

问题描述

我总结了由ID组成的数据框的一列（称为DATA），因此我获得了给定列中每个ID的总数。我想将其转换为另一个数据框（称为TOTALNUM），所以有两列。第一列是ID本身，第二列是每个ID的总数。

I have summarized a column of a data frame (call this DATA) that consists of IDs so I get the total number of each ID in the given column. I'd like to convert this to another data frame (call this TOTALNUM), so I have two columns. The first column is the ID itself and the second column is the total number of each ID. Is this possible?

样本数据：

ids <- c(1,2,3,4,5,1,2,3,1,5,1,4,2,2,2)
info <- c("A","B","C","A","B","C","A","B","C","A","B","C","A","B","C")
DATA <- data.frame(ids, info)
DATA$ids <- as.factor(DATA$ids)

我想放在数据框中的内容：
第一行将是新数据框中的第一列。
第二行将是新数据框中的第二列。

What I would like to put in a data frame: Top row would be the first column in a new data frame. Second row would be the second column in a new data frame.

summary(DATA$ids)

这就是我希望数据框显示的样子：

This is what I would like the data frame to look like:

ids    nums
1      4
2      5
3      2
4      2
5      2

谢谢！

推荐答案

使用这种方法，您可以利用以下事实： summary 返回一个计数向量，每个值的名称为 ids ：

With your approach, you can take advantage of the fact that summary returns a vector of counts, with names for each value of ids:

> my.summary <- summary(DATA$ids)
> data.frame(ids=names(my.summary), nums=my.summary)
  ids nums
1   1    4
2   2    5
3   3    2
4   4    2
5   5    2

或者-这种方法更简单-您可以根据 ids 创建频率表，然后将其转换为数据框：

Or--and this approach is more straightforward--you can create a frequency table based on ids and then convert that to a data frame:

> as.data.frame(table(ids), responseName="nums")
  ids nums
1   1    4
2   2    5
3   3    2
4   4    2
5   5    2

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