Use grepl to search either of multiple substrings in a text [duplicate]

问题

This question already has an answer here:

Matching multiple patterns 6 answers

I am using grepl() in R to search if either of the following Genres exist in my text. I am doing it like this right now:

grepl(\"Action\", my_text) |
grepl(\"Adventure\", my_text) |  
grepl(\"Animation\", my_text) |    
grepl(\"Biography\", my_text) |  
grepl(\"Comedy\", my_text) |    
grepl(\"Crime\", my_text) |  
grepl(\"Documentary\", my_text) |  
grepl(\"Drama\", my_text) |  
grepl(\"Family\", my_text) |  
grepl(\"Fantasy\", my_text) |  
grepl(\"Film-Noir\", my_text) |  
grepl(\"History\", my_text) |  
grepl(\"Horror\", my_text) |  
grepl(\"Music\", my_text) |  
grepl(\"Musical\", my_text) |  
grepl(\"Mystery\", my_text) |  
grepl(\"Romance\", my_text) |  
grepl(\"Sci-Fi\", my_text) |  
grepl(\"Sport\", my_text) |  
grepl(\"Thriller\", my_text) |  
grepl(\"War\", my_text) |    
grepl(\"Western\", my_text)

Is there a better way to write this code? Can I put all the genres in an array and then somehow use grepl() on that?

回答1:

You could paste the genres together with an "or" | separator and run that through grepl as a single regular expression.

x <- c("Action", "Adventure", "Animation", ...)
grepl(paste(x, collapse = "|"), my_text)

Here's an example.

x <- c("Action", "Adventure", "Animation")
my_text <- c("This one has Animation.", "This has none.", "Here is Adventure.")
grepl(paste(x, collapse = "|"), my_text)
# [1]  TRUE FALSE  TRUE

回答2:

You can cycle through a list or vector of genres, as below:

genres <- c("Action",...,"Western")
sapply(genres, function(x) grepl(x, my_text))

To answer your question, if you just want to know if any element of the result is TRUE you can use the any() function.

any(sapply(genres, function(x) grepl(x, my_text)))

Quite simply, if any element of is TRUE, any will return TRUE.

来源：https://stackoverflow.com/questions/26319567/use-grepl-to-search-either-of-multiple-substrings-in-a-text

标签

regex

grepl