Below I am trying to give string arrays to a function that adds unique words to a words array, and if the word is already in the array to increase the count of the corresponding element in the count array:

var words = [];
var counts = [];

calculate([a, b]);
calculate([a, c]);

function calculate(result) {
    for (var i = 0; i < result.length; i++) {
        var check = 0;
        for (var j = 0; i < tags.length; i++) {
            if (result[i] == tags[j]) {
                check = 1;
                counts[i] = counts[i] + 20;
            }
        }
        if (check == 0) {
            tags.push(result[i]);
            counts.push(20);
        }
        check = 0;
    }
}

However the output turns out like this:

words = a, b count = 2, 1

When I expect it to be: words = a,b,c count = 2,1,1

Thanks for any help in advance

Below I am trying to give string arrays to a function that adds unique words to a words array, and if the word is already in the array to increase the count of the corresponding element in the count array:

var words = [];
var counts = [];

calculate([a, b]);
calculate([a, c]);

function calculate(result) {
    for (var i = 0; i < result.length; i++) {
        var check = 0;
        for (var j = 0; i < tags.length; i++) {
            if (result[i] == tags[j]) {
                check = 1;
                counts[i] = counts[i] + 20;
            }
        }
        if (check == 0) {
            tags.push(result[i]);
            counts.push(20);
        }
        check = 0;
    }
}

However the output turns out like this:

words = a, b count = 2, 1

When I expect it to be: words = a,b,c count = 2,1,1

Thanks for any help in advance

• javascript
• arrays

Share Improve this question Follow asked Sep 1, 2014 at 9:06 Grace O'BrienGrace O'Brien 12111 silver badge1111 bronze badges 2

• 3 You declare a words array but never use it. And you use a tags array that's never declared. I assume they're meant to be the same array? – flowstoneknight Commented Sep 1, 2014 at 9:10
• 3 You have the second for loop wrong.. you should iterate over j. j=0; j < tags.length; j++ – Jindra Helcl Commented Sep 1, 2014 at 9:11

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4 Answers 4

Sorted by: Reset to default 2

Breaking the problem down into methods with good names helps you to work out your logic.

Try this:

<script type="text/javascript">
var words = [];
var counts = [];
calculate(["a", "b"]);
calculate(["a", "c"]);
console.log(words);
console.log(counts);

function calculate(result) {
    for (var i=0; i<result.length; i++) {
        if (array_contains(words, result[i])) {
            counts[result[i]]++;
        } else {
            words.push(result[i]);
            counts[result[i]] = 1;
        }
    }
}

function array_contains(array, value) {
    for (var i=0; i<array.length; i++)
        if (array[i] == value)
            return true;
    return false;
}

</script>

Output:

["a", "b", "c"]
[]
a 2
b 1
c 1

Please check this : you can test it on : http://jsfiddle/knqz6ftw/

var words = [];
var counts = [];

calculate(['a', 'b']);
calculate(['a', 'c']);
calculate(['a', 'b', 'c']);

function calculate(inputs) {
    for (var i = 0; i < inputs.length; i++) {
    var isExist = false;
    for (var j = 0; j < words.length; j++) {
        if (inputs[i] == words[j]) {
            isExist = true
            counts[i] = counts[i] + 1;
        }
    }
    if (!isExist) {
        words.push(inputs[i]);
        counts.push(1);
    }
    isExist = false;
}
}

console.log(words);
console.log(counts);

Output is :

["a", "b", "c"] (index):46
[3, 2, 2] 

A few things were wrong, here's working code:

var words = [];
var counts = [];

calculate(["a", "b"]);
calculate(["a", "c"]);

function calculate(result) {
    for (var i = 0; i < result.length; i++) {
        var check = 0;
        for (var j = 0; j < words.length; j++) {
            if (result[i] == words[j]) {
                check = 1;
                ++counts[j];
            }
        }
        if (check == 0) {
            words.push(result[i]);
            counts.push(1);
        }
        check = 0;
    }
}

Jsbin : http://jsbin./hawaco/2/edit?js,console

Things I've changed:

• Changed array literal to supply strings instead of variable names: [a,b] to ["a","b"]
• Replaced instances of tags (presumably an old name) with words
• Changed the 20s to 1s
• Made the increment of counts[j] more clear
• Fixed use of i/j indices

Things to consider:

• Perhaps make this a dictionary rather than a pair of arrays: {"a":1, "b":2}, which would make for simpler code
• Pass in the names of the arrays to permit other accumulators, or bine the method and arrays into a single object

Simplified:

var seen = {};

count(["a", "b"], seen);
count(["a", "c"], seen);

function count(words, accumulator) {
    for (var i = 0; i < words.length; ++i) {
        if(!accumulator.hasOwnProperty(words[i])) {
          accumulator[words[i]] = 1;
        } else {
          ++accumulator[words[i]];
        }
    }
}

Result:

>> seen
[object Object] {
  a: 2,
  b: 1,
  c: 1
}

JSBin: http://jsbin./halak/1/edit?js,console

Here's my solution (using an object):

  const checkWord = (str) => {
    let collection = {};
    // split the string into an array
    let words = str.split(' ');
    words.forEach((word) => {
     collection[word] = word;
   });
   // loop again to check against the array and assign a count
   for (let j = 0; j < words.length; j++) {
     if (words[j] === collection[words[j]]) {
       collection[words[j]] = 0;
     }
     collection[words[j]]++
   }
   console.log(collection);
 };

You can also use reduce:

  const checkWord = (str) => {
  let collection = {};
  let words = str.split(' ');
  words.forEach((word) => {
     collection[word] = word;
   });
  for (var i = 0; i < words.length; i++) {
    if (words[i] === collection[words[i]]) {
      collection[words[i]] = 0;
    }
  }
  let total = words.reduce((occurrences, word) => {
    collection[word]++
    return collection;
}, 0);
    console.log(total);
  };