将重复的列折叠成行 [英] Collapse repeated columns into rows

问题描述

我有一个从API提取的数据框。清洗后，它看起来像这样：

I have a dataframe that I pulled in from an API. After some cleaning it looks something like this:

Title   Year  Rating  Title    Year  Rating  Title    Year  Rating
Movie 1 1997  6.7     Movie 2  1987  8.2     Movie 3  2009  7.1

列标题重复，在这种情况下，单行包含3个单独的条目。

The column headers repeat, and in this case a single row contains 3 separate entries.

我将如何重塑它，以便最终得到3列（标题，年份，评分）和3行（电影1，电影2，电影3）？

How would I reshape this so that I end up with 3 columns (Title, Year, Rating) and 3 rows (Movie 1, Movie 2, Movie 3)?

最简单的方法是什么？

推荐答案

将输入data.frame转换为列表，然后根据其公共列名将各列分为几组。然后取消列出每组列，以在每组中产生一个列，然后转换回data.frame。 （如果 DF 中有多行，这也适用。）

Convert the input data.frame to a list and split the columns into groups according to their common column names. Then unlist each group of columns to produce a single column in each group and convert back to a data.frame. (This also works if there is more than one row in DF.)

as.data.frame(lapply(split(as.list(DF), names(DF)), unlist))

给予：

  Rating  Title Year
1    6.7 Movie1 1997
2    8.2 Movie2 1987
3    7.1 Movie3 2009

注意：此输入：

Lines <- "Title   Year  Rating  Title    Year  Rating  Title    Year  Rating
Movie1 1997  6.7     Movie2  1987  8.2     Movie3  2009  7.1"
DF <- read.table(text = Lines, header = TRUE, check.names = FALSE, as.is = TRUE)

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