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Inverted index: Difference between revisions
→{{header|Scala}}
(added Clojure version) |
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Line 2,236:
> ./indexsearch.rb It iS\!
["file1", "file2", "file3"]</pre>
=={{header|Scala}}==
<lang Scala>object InvertedIndex extends App {
import java.io.File
// indexer
val WORD = raw"(\w+)".r
def parse(s: String) = WORD.findAllIn(s).map(_.toString.toLowerCase)
def invertedIndex(files: Seq[File]): Map[String,Set[File]] = {
var i = Map[String,Set[File]]() withDefaultValue Set.empty
files.foreach{f => scala.io.Source.fromFile(f).getLines flatMap parse foreach
(w => i = i + (w -> (i(w) + f)))}
i
}
// user interface
args match {
case _ if args.length < 2 => println("Usage: InvertedIndex ALLSEARCHWORDS FILENAME...")
case Array(searchwords, filenames @ _*) =>
val queries = parse(searchwords).toList
val files = filenames.map(new File(_)).filter{f => if (!f.exists) println(s"Ignoring $f"); f.exists}
(queries, files) match {
case (q, _) if q.isEmpty => println("Missing search words")
case (_, f) if f.isEmpty => println("Missing extant files")
case _ => val index = invertedIndex(files)
println(s"""Searching for ${queries map ("\""+_+"\"") mkString " and "} in ${files.size} files:""")
queries.map(index).foldLeft(files.toSet)(_ intersect _) match {
case m if m.isEmpty => println("No matching files")
case m => println(m mkString "\n")
}
}
}
}</lang>
{{out}}
<pre>> InvertedIndex "the" file1.txt file2.txt file3.txt
Searching for "the" in 3 files:
data/file1.txt
data/file2.txt
data/file3.txt
> InvertedIndex "the cat sat" file1.txt file2.txt file3.txt
Searching for "the" and "cat" and "sat" in 3 files:
file1.txt
file2.txt
> InvertedIndex fox file1.txt file2.txt file3.txt
Searching for "fox" in 3 files:
file3.txt
> InvertedIndex abc file1.txt file2.txt file3.txt
Searching for "abc" in 3 files:
No matching files</pre>
=={{header|Tcl}}==
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