MultiDimenaional Array sort

[Joe San]

Guys,

How could I sort a multidimensional array in a javascript. I tried the following but it gives me undefined as the value when I try to sort it.

output = new Array();

//code not shown....I iterate over a loop and populate my array...and when I alert it, I get the following

Jothi: 1, Density: 25, Shankar: 2, Density: 50

Now I want to sort them in descending order based on the Density number and here is what I did,

function sortByDensity(a, b) {
    var x = a.Density;
    alert("The value obtained is " + a.Density); //get undefined...Any idea as to why??
    var y = b.Density;
    return ((x < y) ? -1 : ((x > y) ? 1 : 0));
}

and simply do,
output.sort(sortByDensity); //to sort my array based on Density

Help me out guys!

[Eric Pascarello]

have a script on my blog, see if it helps:

http://radio.javaranch.com/pascarello/2009/05/29/1243615124260.html

Eric

[Joe San]

That seems to give me some other results...it even includes the entire function as an additional element.

But what is wrong in the script that I provided above?

[Eric Pascarello]

I am guessing you have a problem with your array. How are you doing the looping and adding to it?

Eric

[Joe San]

Here is the entire javascript,

<script language="JavaScript">
function count(txt_element)
{
   str=document.getElementById(txt_element).value;
   var newStr = "a";
   alert("The actual String is " + str);
   var words = str.replace(/[^a-zA-Z0-9]/g,' ').split(' ');
   var assoc = new Array();
   total_words=words.length;

 stopwords = [ "a", "about", "above", "accordingly", "after",
  "again", "against", "ah", "all", "also", "although", "always", "am", "among", "amongst", "an",
  "and", "any", "anymore", "anyone", "are", "as", "at", "away", "be", "been",
  "begin", "beginning", "beginnings", "begins", "begone", "begun", "being",
  "below", "between", "but", "by", "ca", "can", "cannot", "come", "could",
  "did", "do", "doing", "during", "each", "either", "else", "end", "et",
  "etc", "even", "ever", "far", "ff", "following", "for", "from", "further", "furthermore",
  "get", "go", "goes", "going", "got", "had", "has", "have", "he", "her",
  "hers", "herself", "him", "himself", "his", "how", "i", "if", "in", "into",
  "is", "it", "its", "itself", "last", "lastly", "less", "many", "may", "me",
  "might", "more", "must", "my", "myself", "near", "nearly", "never", "new",
  "next", "no", "not", "now", "o", "of", "off", "often", "oh", "on", "only",
  "or", "other", "otherwise", "our", "ourselves", "out", "over", "perhaps",
  "put", "puts", "quite", "s", "said", "saw", "say", "see", "seen", "shall",
  "she", "should", "since", "so", "some", "such", "t", "than", "that", "the",
  "their", "them", "themselves", "then", "there", "therefore", "these", "they",
  "this", "those", "though", "throughout", "thus", "to", "too",
  "toward", "unless", "until", "up", "upon", "us", "ve", "very", "was", "we",
  "were", "what", "whatever", "when", "where", "which", "while", "who",
  "whom", "whomever", "whose", "why", "with", "within", "without", "would",
  "yes", "your", "yours", "yourself", "yourselves" ];


function isStopword(stopWordArray, element) {
  var flag = 0;
  for (var i = 0; i < stopWordArray.length; i++) {
    if (stopWordArray[i].toLowerCase() == element.toLowerCase()) {
      //str = str.replace(element, "");
      flag = 1;
    }
  }
  if (flag == 0) {
    newStr = newStr + " " + element;
  }
}


for(i=0; i<total_words; i++) {
  isStopword(stopwords, words[i]);
}


alert("The final String is NEW STR...." + newStr);

var newWords = newStr.replace(/[^a-zA-Z0-9]/g,' ').split(' ');

alert("The new words are " + newWords);
var new_total_words=newWords.length;

   for (i=0; i><new_total_words; i++)
   {
      if (!newWords[i])
         continue;
      if (assoc[newWords[i]] == null)
         assoc[newWords[i]]=0;
      assoc[newWords[i]]++;
   }
   output = new Array();

   for (word in assoc)
   {
      output[output.length]=word + ": " + assoc[word] + ", Density: " + Math.round((assoc[word]/new_total_words)*100);
   }
   alert(output);
   alert("The first element in the array is " + output[0]);
   alert("The second element in the array is " + output[1]);
   output.sort(sortByDensity);
   document.getElementById('outputId').innerHTML="<b>Keyword Density</b><br/><i>Total Words:"+new_total_words+"></i><br/>"+output.join('<br/>');
}

function sortByDensity(a, b) {
    var x = a.Density;
    alert("The value obtained is " + a.Density);
    var y = b.Density;
    return ((x < y) ? -1 : ((x > y) ? 1 : 0));
}

</script>

The output.sort(sortByDensity) seems not to be working! Any clue?

[Joe San]

I'm trying to do the following,

(1) In the text which is entered in the textarea, I would filter out the stop words
(2) Find out the keyword density
(3) Take the first 3 words and send them to the server using a form submit

I'm stuck with the above example. Please help!

[Joe San]

Eric,

Am I doing anything wrong here?

[Eric Pascarello]

This is a string:

output[output.length]=word + ": " + assoc[word] + ", Density: " + Math.round((assoc[word]/new_total_words)*100);

You can not treat that as an object like you do

It should be

output[output.length]= {"word": assoc[word], "Density": Math.round((assoc[word]/new_total_words)*100) };

Now you have an object

Eric

[Joe San]

But that did not help either....Got the below output,

Keyword Density
Total Words:25
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]
[object Object]

[Eric Pascarello]

So now you need to change your output code to loop through the array and read the objects.

Eric

[Joe San]

But why would it not sort?

[Joe San]

I'm just trying to look for a solution here. Please help me Eric!

[Eric Pascarello]

I am trying to help you learn.

You created a String

var str = "word:foo, Density: 23.4567890"; 

In Java, would you be able to reference things out of a string like a hash? no, you can not do that in JavaScript either. So you need an object in each index so you can use dot notation.

Since you have objects when you convert it to a string [via join] it says Object. So you need to loop through your array, index by index and read your properties of each individual object.

Eric

[Joe San]

I infact did loop through it and now started to get some other errors which looks totally irrelevant. Below is the entire stuff that I did,

<html>
<head>
<title>JavaScript Keyword Density Analyzer</title>
<script language="JavaScript">
function count(txt_element)
{
   str=document.getElementById(txt_element).value;
   var newStr = "a";
   alert("The actual String is " + str);
   var words = str.replace(/[^a-zA-Z0-9]/g,' ').split(' ');
   var assoc = new Array();
   total_words=words.length;

 stopwords = [ "a", "about", "above", "accordingly", "after",
  "again", "against", "ah", "all", "also", "although", "always", "am", "among", "amongst", "an",
  "and", "any", "anymore", "anyone", "are", "as", "at", "away", "be", "been",
  "begin", "beginning", "beginnings", "begins", "begone", "begun", "being",
  "below", "between", "but", "by", "ca", "can", "cannot", "come", "could",
  "did", "do", "doing", "during", "each", "either", "else", "end", "et",
  "etc", "even", "ever", "far", "ff", "following", "for", "from", "further", "furthermore",
  "get", "go", "goes", "going", "got", "had", "has", "have", "he", "her",
  "hers", "herself", "him", "himself", "his", "how", "i", "if", "in", "into",
  "is", "it", "its", "itself", "last", "lastly", "less", "many", "may", "me",
  "might", "more", "must", "my", "myself", "near", "nearly", "never", "new",
  "next", "no", "not", "now", "o", "of", "off", "often", "oh", "on", "only",
  "or", "other", "otherwise", "our", "ourselves", "out", "over", "perhaps",
  "put", "puts", "quite", "s", "said", "saw", "say", "see", "seen", "shall",
  "she", "should", "since", "so", "some", "such", "t", "than", "that", "the",
  "their", "them", "themselves", "then", "there", "therefore", "these", "they",
  "this", "those", "though", "throughout", "thus", "to", "too",
  "toward", "unless", "until", "up", "upon", "us", "ve", "very", "was", "we",
  "were", "what", "whatever", "when", "where", "which", "while", "who",
  "whom", "whomever", "whose", "why", "with", "within", "without", "would",
  "yes", "your", "yours", "yourself", "yourselves", ",", ";", "?", ".", "$", " ", "example", "using"];


function isStopword(stopWordArray, element) {
//alert("Element is " + element);
  var flag = 0;
  for (var i = 0; i < stopWordArray.length; i++) {
    if (stopWordArray[i].toLowerCase() == element.toLowerCase()) {
      //str = str.replace(element, "");
      flag = 1;
    }
    if (element == " " || element == "") {
      flag = 1;
    }
  }
  if (flag == 0) {
    newStr = newStr + " " + element;
  }
//alert("Flag is " + flag);
}


for(i=0; i<total_words; i++) {
  isStopword(stopwords, words[i]);
}


alert("The NEW STR...." + newStr);

var newWords = newStr.replace(/[^a-zA-Z0-9]/g,' ').split(' ');

alert("The new words are " + newWords);
var new_total_words=newWords.length;

   for (i=0; i><new_total_words; i++)
   {
      if (!newWords[i])
         continue;
      if (assoc[newWords[i]] == null)
         assoc[newWords[i]]=0;
      assoc[newWords[i]]++;
   }
   output = new Array();
   outputDensity = new Array();
   outputArray = new Array();

   topThreeArray = new Array(3);

   for (word in assoc)
   {
      //outputArray[outputArray.length] = word + "," + Math.round((assoc[word]/new_total_words)*100)
      //output[output.length]=word + ": " + assoc[word] + ", Density: " + Math.round((assoc[word]/new_total_words)*100);
      //outputDensity[outputDensity.length]="Density: " + Math.round((assoc[word]/new_total_words)*100) + ", " + word + ": " + assoc[word];
     output[output.length]= {"word": assoc[word], "Density": Math.round((assoc[word]/new_total_words)*100) };


   }
   //alert("First element in the array " + outputArray[0]);
   //alert("Second element in the array " + outputArray[1]);
   //outputArray.sort(sortByDensity);
   //outputArray.reverse();
   //alert("After sorting " + outputArray);


   printResults(output);

   //document.getElementById('outputId').innerHTML="<b>Keyword Density</b><br/><i>Total Words:"+new_total_words+"></i><br/>"+output.join('<br/>');
}


function sortByDensity(a, b) {
//alert("A density is " + a[2]);
    //var x = a.Density;
    //var y = b.Density;
    //return ((x < y) ? -1 : ((x > y) ? 1 : 0));
    return ((a[1] < b[1]) ? -1 : ((a[1] > b[1]) ? 1 : 0));
}

function printResults(arr) {
  for(int i =0; i<arr.length; i++) {
   for(int k =0; k><arr.length; k++) {
      alert(arr[i][k]);
   }
  }

}

></script>
</head>
<body>
<h2>JavaScript Keyword Density Analyzer</h2>
<textarea name="txt_text" id="txtId" cols="50" rows="5"></textarea><br/><br/>
<input type="submit" name="Submit" value="Calculate Keyword Density" onClick="javascript: count('txtId');">
<br/><br/>
<div id="outputId"></div>
</body>
</html>

When I tried running it, it gave me Object Expected at line 126, which looks totally irrevevant!

[Sean Clark]

function printResults(arr)

This is the function that you need to have a look at, I don't think you are dealing with the object correctly to output it.
Firstly, I don't think it is a 2D array, more like a List<Map> in java terms.

Sean

[Eric Pascarello]

You do not have a multiple dimensional array, a multiple dimensional array would look like

[[1,2],[2,3],[4,5]]

so my first link would not work.

You should have left

# //var x = a.Density;
# //var y = b.Density;
# //return ((x < y) ? -1 : ((x > y) ? 1 : 0));

alone.

Eric

[Joe San]

I did not quite get you. Can you be clear?

[Eric Pascarello]

You need to do the sort the way you originally did it.

Eric

[Joe San]

Man this is really getting me irritated. I have made some refactoring to the HTML and have started a new topic here just to avoid confusions.

I gave up sorting and now just getting the top three elements and will be continued in this post https://coderanch.com/t/460904/HTML-JavaScript/Getting-top-keywords-from-text#2057070.

[Joe San]

Eric,

I gave up sorting. Can you please help me out with the other post from the link that I gave above? Any yes, please close this post!