How do I search a string in JavaScript array using jQuery?

I have a JavaScript array:

var j_array = new Array();
j_arry=["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];

I need to find how many times the class is coming and its array key, so I use:

found = $.inArray('class', j_array); ` But it returns `-1`;

Then I use:

var search = 'class';
$.each([j_array], function(index, value){
    $.each(value, function(key, cell){
        if (search.indexOf(cell) !== -1)
            console.log('found in array '+index, cell);
    });
});

But that is also wrong. How do I solve this?

From this array I want to get the following:

1. Class coming 4 times, at key 0, 2, 3, and 7




2. I want to make a separate array of class only, that is,

   
   
   
   

   new_array = ["class:1", "class:2", "class:3", "class:10"];
   




3. Currently there are four classes in j_array. How can I get the Nth class value

That is, 1st class value ="class:1", 2nd class value="class:5", etc.

Answer

Use Array.prototype.filter to filter out the elements of the array that contains the string class - see demo below:

var j_array =["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];

var result = j_array.filter(function(e){
  return e.indexOf('class')!==-1;
});

console.log(result);

EDIT:

To get the list of indexes too, you can try this:

var j_array =["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];


var filteredIndices = []

var filtered = j_array.filter(function(e,i){
  if(e.indexOf('class')!==-1) {
    filteredIndices.push(i);
    return true;
  } else {
    return false;
  }
});


console.log(filtered);
console.log(filteredIndices);

// Nth class value
console.log(filtered[2]); // this prints the 3rd one

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