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I have a folder holding a set of different data files. I would like to count the number of files that contain a given term, like "25" or "color coding", and if possible, listing the name of those files. Are they any ways to do that in R?

user785099
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    Yes, I'm sure there are. [What have you tried?](http://whathaveyoutried.com) (Although, as a hint, if you're trying to search files for a given string, this kind of task is not well suited to R.) –  Nov 12 '12 at 16:46
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    The best way to do it depends quite a bit on what the format of the files is. – Drew Steen Nov 12 '12 at 16:47
  • Does [this](http://stackoverflow.com/questions/371115/count-all-occurrences-of-string-in-lots-of-files-with-grep) help? – liuminzhao Nov 12 '12 at 16:53

1 Answers1

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Does this do what you need

findTermsInFileNames <- function(terms, theFolder="path/to/Folder/", extension="R", ignoreCase=TRUE)  {
  # Iterates through all files of type `extension` in `theFolder` and returns a 
  #  count for each time one of `terms` appears in a file name
  # Note:  extension should NOT include a dot.  good: "*"  bad: ".*"

  # str_detect is from stringr
  require(stringr)

  # Get list of files
  pat <- paste0("*.", extension)
  filesList <- list.files(path.expand(theFolder), pattern=pat, ignore.case=ignoreCase)

  # Add attribute to terms, whether cAseS should be ignored
  attr(terms, "ignore.case") <- ignoreCase

  # Tabulate all occurrences of temrs in the list of file names
  results <- rowSums(sapply(filesList,  str_detect, terms, USE.NAMES=TRUE)) 

  # Clean up the table names
  names(results) <- terms

  return(results)
}

Example: 

fold <- "~/git/src"
terms <- c("an", "example", "25")

findTermsInFileNames(terms, fold)
Ricardo Saporta
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