3

I'm trying to create a dictionary from a .txt file in the shape of a tree. On every line of the text file there's a word, I extract all those words in an array.

Now regarding the tree, Each node contains a letter, if it's the last letter of a word, it contains a definition, and each node have an array Children that contains letters from all others words starting the same way.

So I have nodes defined this way:

function Node(letter,definition,children) {
   this.letter = letter,
   this.definition = "",
   this.children = [] 
};

I have an array Dictionary that will contain all the nodes. Every Node will be organized (so that we know 'a' is in Dictionary[0] and 'b' in Dictionary[1] and so on).

I defined some functions to help build the dictionary:

  • check if Dictionary contains the first letter of the word we have (c is the character, dictio is the dictionary array and ascii is the ascii-97 value of the character)

    function checkChar(c,dictio,ascii){
    if(dictio[ascii].letter == c ){
        return true;
    }
    return false;
};

    • create a node with the given character

      function createChar(c){

    var noeud = {
        letter: c,
        def: '',
        children: [] 
    };

    return noeud;
};

  • Add the character to the dictionary

    function addChar(c,dictio,ascii){ dictio.children[ascii] = createChar(c); };

  • And I'm having trouble on the biggest function: the main on that adds the word and calls all of these small functions I've written. Which I'm having trouble making.

I don't even know if what I'm doing is right or wrong, if anyone could point me to the right direction or suggest a method in javascript or php to do dictionary from a TXT file that would be great.

Improve this question
11
  • This is an interesting concept... what is your goal? Commented Apr 1, 2015 at 16:00
  • function Node(letter,definition,children) = {}; --> syntax error? Commented Apr 1, 2015 at 16:05
  • @IsmaelMiguel Yes sorry, didn't copy well, there's not = sign and Jason: Just some work to try to learn and understand a bit more trees and JS Commented Apr 1, 2015 at 16:31
  • You can try to implement this using Objects. Instead of you having functions scattered across your code, you create a new Object and it will have all the required methods to work. Everything contained in a single instance. Commented Apr 1, 2015 at 17:00
  • Can you give some more inforamtion like: real example in your question? what is the purpose of 'definition'? if you could supply these I could give you a PHP implementation. Commented Apr 1, 2015 at 17:13

2 Answers 2

Reset to default
1

Ok...

so this is an example of txt file containing words

//words.txt
hello
world
foo
bar

word_dictionary.php for parsing txt file and has method for checking if a word exists in tree/dictionary

<?php 
//word_dictionary.php
class Node{
    private $letter;
    private $definition = '';
    private $children = array();

    function __construct($letter){
        $this->letter = $letter;
    }

    function hasChild($letter){
        return array_key_exists($letter,$this->children);
    }

    function addChild($letter){
        $this->children[$letter] = new Node($letter);
        return $this->children[$letter];
    }

    function getChild($letter){
        return $this->children[$letter];
    }

    function setDefinition($definition){
        $this->definition = $definition;
    }

    function getDefinition(){
        return $this->definition;
    }

    function hasDefinition(){
        return (bool)$this->definition;
    }
}

// method for getting a word definition from tree/dictionary.
// if word exists return definition, else return false
function getDefinition($word,$tree){
    $node = $tree;
    $length = strlen($word);
    foreach(str_split($word) as $index => $letter){
        if($node->hasChild($letter)){
            $node = $node->getChild($letter);
        }
        else{   // word not exists
            return false;
        }
        if(($index+1) == $length){      // means last letter in word
            return ($node->hasDefinition()) ? $node->getDefinition() : false;
        }
    }   
}

// Start build your tree/dictionary. This part is execute ONCE only for building tree.
$anchor = new Node('');
$handle = fopen('words.txt','r');
while(($word = fgets($handle))){
    $word = rtrim($word);
    $length = strlen($word);
    $node = $anchor; 
    foreach(str_split($word) as $index => $letter){

        if($node->hasChild($letter)){
            $node = $node->getChild($letter);
        }
        else{
            $node = $node->addChild($letter);
        }

        if(($index+1) == $length ){
            //print 'definition for word: '.$word."\n";
            $node->setDefinition('definition for world: '.$word);   
        }
    }
} 

//use this function when a user type a word that you want to check if exists and return the definition to user. this flow should be in AJAX request from client 
print getDefinition('bar',$anchor)."\n";

hope it help a bit ;)

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

0

first of all, you're asking if you are going in the right direction. Well, i think you are. This may not be the best implementation of the year but still all the things you said are coherent with each other and it seems pretty solid.

I don't think giving you a direct solution to your question would be didactic since you're working with trees and it seems you don't have much experience with them.

But i can give you some hint and references. A very convenient way to implement your "biggest function :)" would be to use a recursive function which would call itself on each children.

I suggest you take a look a this wikipedia article. It shows example of trees that look a bit like yours and implement a full search algorithm that you could adapt to your needs without too much problem.

Hope the english wasn't that bad, and that it will help you

Improve this answer

1 Comment

Alright thanks, I'm going to look into that direction :)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.