问题
Hi friends I am trying to search particular keywords (given in txt) in a list of files.I am using a regular expression to detect and replace the occurrence of the keyword in a file. Below is a comma separated keywords that i am passing to be searched.
library(stringi)
txt <- "automatically got activated,may be we download,network services,food quality is excellent"
Ex "automatically got activated" should be searched and replaced by automatically_got_activated..."may be we download" replaced by "may_be_we_download" and so on.
txt <- "automatically got activated,may be we download,network services,food quality is excellent"
for(i in 1:length(txt)) {
start <- head(strsplit(txt, split=" ")[[i]], 1) #finding the first word of the keyword
n <- stri_stats_latex(txt[i])[4] #number of words in the keyword
o <- tolower(regmatches(text, regexpr(paste0(start,"(?:[^a-zA-Z'-]+[a-zA-Z'-]+){0,",
n-1,"}"),text,ignore.case=TRUE))) #best match for keyword for the regex in the file
p <- which(!is.na(pmatch(txt, o))) #exact match for the keywords
}
回答1:
I think this may be what you're looking for.
> txt <- "automatically got activated,may be we download,network services,food quality is excellent"
A made-up vector of sentences to search from:
> searchList <- c('This is a sentence that automatically got activated',
'may be we download some music tonight',
'I work in network services',
'food quality is excellent every time I go',
'New service entrance',
'full quantity is excellent')
A function to do the work:
replace.keyword <- function(text, toSearch)
{
kw <- unlist(strsplit(txt, ','))
gs <- gsub('\\s', '_', kw)
sapply(seq(kw), function(i){
ul <- ifelse(grepl(kw[i], toSearch),
gsub(kw[i], gs[i], toSearch),
"")
ul[nzchar(ul)]
})
}
The results:
> replace.keyword(txt, searchList)
# [1] "This is a sentence that automatically_got_activated"
# [2] "may_be_we_download some music tonight"
# [3] "I work in network_services"
# [4] "food_quality_is_excellent every time I go"
Let me know if it works for you.
来源:https://stackoverflow.com/questions/23782506/regular-expression-to-search-and-replace-a-string-in-a-file