Question

我有一个像这样的列的数据框

 Id   Comment 
 1     \u009cYes yes for ever for ever the boys cried in their ringing voices   with softened faces on 02/14/2016
 2     \u009cYes yes for ever for ever the cried in their ringing voices with softened faces on 01/14/2010
 3     \u009cYes yes for ever for ever t 12/04/2003
 4     \u009c for ever for ever ringing voices  07/02/2002
 5     \u009c for ever for ever ringing softened faces  07/09/2001

如何使用gsub替换除ringing和02/14/2016

之外的所有字符

最后一栏应该是这样的

Id    Comment
1     ringing 02/14/2016
2     ringing 01/14/2010
3             12/04/2003
4     ringing 07/02/2002
5     ringing 07/09/2001

-----根据G.Grothendieck，Frank和Dason的评论更新了问题

Answer 1

怎么样：

df <- read.table(text="Id,Comment 
1,\u009cYes yes for ever for ever the boys cried in their ringing voices   with softened faces on 02/14/2016
2,\u009cYes yes for ever for ever the cried in their ringing voices with softened faces on 01/14/2010
3,\u009cYes yes for ever for ever t 12/04/2003
4,\u009c for ever for ever ringing voices  07/02/2002
5,\u009c for ever for ever ringing softened faces  07/09/2001", header=T, sep=",")

df$ringing <- ''
df[grep("ringing", df$Comment), 'ringing'] <- 'ringing'
df[grep("../../..", df$Comment), 'date'] <- regmatches(df$Comment,regexpr("../../..", df$Comment))
df$res <- paste(df$ringing, df$date)

Answer 2

您可以使用dplyr，如下所示。虽然可能有更好的方法来处理正则表达式（即不需要paste）。这假定数据已经在df。

library(dplyr)
df %>%
    mutate(Comment = paste0( ifelse(grepl('ringing', Comment), 'ringing ', ''),
                             gsub('^.*(\\d{2}/\\d{2}/\\d{4}).*', '\\1', Comment)))

gsub替换一切，但

2 个答案: