Task: Inverted index




Go: package main

import (
    "bufio"
    "bytes"
    "errors"
    "fmt"
    "io"
    "os"
)


var index map[string][]int 
var indexed []doc

type doc struct {
    file  string
    title string
}

func main() {
    
    index = make(map[string][]int)

    
    if err := indexDir("docs"); err != nil {
        fmt.Println(err)
        return
    }

    
    ui()
}

func indexDir(dir string) error {
    df, err := os.Open(dir)
    if err != nil {
        return err
    }
    fis, err := df.Readdir(-1)
    if err != nil {
        return err
    }
    if len(fis) == 0 {
        return errors.New(fmt.Sprintf("no files in %s", dir))
    }
    indexed := 0
    for _, fi := range fis {
        if !fi.IsDir() {
            if indexFile(dir + "/" + fi.Name()) {
                indexed++
            }
        }
    }
    return nil
}

func indexFile(fn string) bool {
    f, err := os.Open(fn)
    if err != nil {
        fmt.Println(err)
        return false 
    }

    
    x := len(indexed)
    indexed = append(indexed, doc{fn, fn})
    pdoc := &indexed[x]

    
    r := bufio.NewReader(f)
    lines := 0
    for {
        b, isPrefix, err := r.ReadLine()
        switch {
        case err == io.EOF:
            return true
        case err != nil:
            fmt.Println(err)
            return true
        case isPrefix:
            fmt.Printf("%s: unexpected long line\n", fn)
            return true
        case lines < 20 && bytes.HasPrefix(b, []byte("Title:")):
            
            
            
            pdoc.title = string(b[7:])
        }
        
        
        
    wordLoop:
        for _, bword := range bytes.Fields(b) {
            bword := bytes.Trim(bword, ".,-~?!\"'`;:()<>[]{}\\|/=_+*&^%$#@")
            if len(bword) > 0 {
                word := string(bword)
                dl := index[word]
                for _, d := range dl {
                    if d == x {
                        continue wordLoop
                    }
                }
                index[word] = append(dl, x)
            }
        }
    }
    return true
}

func ui() {
    fmt.Println(len(index), "words indexed in", len(indexed), "files")
    fmt.Println("enter single words to search for")
    fmt.Println("enter a blank line when done")
    var word string
    for {
        fmt.Print("search word: ")
        wc, _ := fmt.Scanln(&word)
        if wc == 0 {
            return
        }
        switch dl := index[word]; len(dl) {
        case 0:
            fmt.Println("no match")
        case 1:
            fmt.Println("one match:")
            fmt.Println("   ", indexed[dl[0]].file, indexed[dl[0]].title)
        default:
            fmt.Println(len(dl), "matches:")
            for _, d := range dl {
                fmt.Println("   ", indexed[d].file, indexed[d].title)
            }
        }
    }
}




Python: 

from pprint import pprint as pp
from glob import glob
try: reduce
except: from functools import reduce
try:    raw_input
except: raw_input = input


def parsetexts(fileglob='InvertedIndex/T*.txt'):
    texts, words = {}, set()
    for txtfile in glob(fileglob):
        with open(txtfile, 'r') as f:
            txt = f.read().split()
            words |= set(txt)
            texts[txtfile.split('\\')[-1]] = txt
    return texts, words

def termsearch(terms): 
    return reduce(set.intersection,
                  (invindex[term] for term in terms),
                  set(texts.keys()))

texts, words = parsetexts()
print('\nTexts')
pp(texts)
print('\nWords')
pp(sorted(words))

invindex = {word:set(txt
                        for txt, wrds in texts.items() if word in wrds)
            for word in words}
print('\nInverted Index')
pp({k:sorted(v) for k,v in invindex.items()})

terms = ["what", "is", "it"]
print('\nTerm Search for: ' + repr(terms))
pp(sorted(termsearch(terms)))