R grep：有AND运算符吗？ [英] R grep: is there an AND operator?

问题描述

假设我有以下数据框：

  User.Id标签
 34234 imageUploaded，people.jpg，更多，逗号，分隔，东西
 34234 imageUploaded 
 12345 people.jpg 
  

我如何使用grep（或其他工具）来只抓取包含imageUploaded和people的行？换句话说，我如何创建一个包含字符串imageUploaded和people.jpg的行的子集，无论订单如何。

我试过了：

  data.people< -data [grep（imageUploaded | people.jpg，results $ Tags），] 
 data.people< -data [grep（imageUploaded？= people.jpg，results $ Tags），] 
  

是否有AND运算符？或者也许另一种方式来获得预期的结果？

解决方案

感谢这个答案，这个正则表达式似乎工作。你想使用 grepl（），它返回一个逻辑索引到你的数据对象中。我不会声称完全理解正则表达式的内部运作，但不管：

  x < -  c（imageUploaded ，people.jpg，more，comma，separated，stuff，imageUploaded，people.jpg）
 
 grepl（（？=。* imageUploaded）（？=。* people \ \.jpg），x，perl = TRUE）
＃----- 
 [1] TRUE FALSE FALSE 
  

Suppose I have the following data frame:

User.Id    Tags
34234      imageUploaded,people.jpg,more,comma,separated,stuff
34234      imageUploaded
12345      people.jpg

How might I use grep (or some other tool) to only grab rows that include both "imageUploaded" and "people"? In other words, how might I create a subset that includes just the rows with the strings "imageUploaded" AND "people.jpg", regardless of order.

I have tried:

data.people<-data[grep("imageUploaded|people.jpg",results$Tags),]
data.people<-data[grep("imageUploaded?=people.jpg",results$Tags),]

Is there an AND operator? Or perhaps another way to get the intended result?

解决方案

Thanks to this answer, this regex seems to work. You want to use grepl() which returns a logical to index into your data object. I won't claim to fully understand the inner workings of the regex, but regardless:

x <- c("imageUploaded,people.jpg,more,comma,separated,stuff", "imageUploaded", "people.jpg")

grepl("(?=.*imageUploaded)(?=.*people\\.jpg)", x, perl = TRUE)
#-----
[1]  TRUE FALSE FALSE

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