将strsplit的结果分配给多列数据框

Question

我试图在数据框内将字符向量分成三个不同的向量.

我的数据类似于:

> df <- data.frame(filename = c("Author1 (2010) Title of paper", 
                                "Author2 et al (2009) Title of paper",
                                "Author3 & Author4 (2004) Title of paper"),
                   stringsAsFactors = FALSE)

我想这3个信息(拆分authors,year,title)分成三个不同的列,所以,这将是:

> df
                          filename             author  year   title
 1           Author1 (2010) Title1            Author1  2010  Title1
 2     Author2 et al (2009) Title2      Author2 et al  2009  Title2
 3 Author3 & Author4 (2004) Title3  Author3 & Author4  2004  Title3

我习惯在3个元素的向量中strsplit分割每个filename元素:

 df$temp <- strsplit(df$filename, " \\(|\\) ")

但现在,我找不到将每个元素放在单独列中的方法.我可以访问这样的特定信息:

> df$temp[[2]][1]
[1] "Author2 et al"

但无法找到如何将其放在其他列中

> df$author <- df$temp[[]][1]
Error

Answer 1

你可以试试tstrsplitdevel版本data.table

library(data.table)#v1.9.5+
 setDT(df)[, c('author', 'year', 'title') :=tstrsplit(filename, ' \\(|\\) ')]
df
#                                  filename             author year
#1:           Author1 (2010) Title of paper           Author1  2010
#2:     Author2 et al (2009) Title of paper     Author2 et al  2009
#3: Author3 & Author4 (2004) Title of paper Author3 & Author4  2004
#             title
#1:  Title of paper
#2:  Title of paper
#3:  Title of paper

编辑:包含OP的拆分模式以删除空格.

Answer 2

有了这个tidyr包,这是一个separate解决方案:

separate(df, "filename", c("Author","Year","Title"), sep=" \\(|\\) "), remove=F)
#                                  filename            Author
# 1           Author1 (2010) Title of paper           Author1
# 2     Author2 et al (2009) Title of paper     Author2 et al
# 3 Author3 & Author4 (2004) Title of paper Author3 & Author4
#   Year          Title
# 1 2010 Title of paper
# 2 2009 Title of paper
# 3 2004 Title of paper

领先和尾随空间已被考虑在内

Answer 3

result <- cbind(df, do.call("rbind", strsplit(df$filename, " \\(|\\) ")))
colnames(result)[2:4] <- c("author", "year", "title")