count number of character occurrences in a sentence

Question

I'm writing a code where users can input any text and choose any letter to see how many times it occurred in that particular text - I'm not sure where I'm going wrong

function textOccurrences() {
  var inputField1 = (document.getElementById("inputField1").value);
  var inputField2 = (document.getElementById("inputField2").value);
  var count = 0;

  for (i = 0; i < length; i++) {
    if (parseInt(search) != -1) {
      count++;
      var search = inputField1.indexOf(inputField2, parseInt(search) + 1);
    }
    document.getElementId("answer").value = inputField2 + "Occurs" + count + "times";
  }
}

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title> Text Occurrences </title>
  <h1> Number of Character Occurrences</h1>
  <script="text/javascript"> </script>
</head>

<body>
  <form>
    <p>Enter text: </p>
    <p> <input id="inputField1" type="text" /> </p>

    <p>Enter any character:</p>
    <p> <input id="inputField2" type="text" /> </p>
    <input type="button" value="Search" onlick="textOccurrences()" />
    </p>
    <p>Number of Occurrences:</p>
    <p><textarea id="answer"></textarea></p>
  </form>
</body>

</html>

Possible duplicate of [How to count string occurrence in string?](https://stackoverflow.com/questions/4009756/how-to-count-string-occurrence-in-string) — Striped, Mar 26 '18 at 16:07
change `onlick="textOccurrences()"` to `onclick="textOccurrences()"`, that is the reason nothing happened when you click **Search** button. And you need to declare **search** and **length** first. — Sphinx, Mar 26 '18 at 16:08
@zfrisch No, TO isn't. `search` is _only_ undefined -> [`var` hoisting](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var#var_hoisting) — Andreas, Mar 26 '18 at 16:09
It is always awkward to lick my screen in public. These new HTML events are getting crazy! — epascarello, Mar 26 '18 at 16:09
@Andreas You're right. since ES6 I've been operating under the assumption that var hoisting had been completely removed but apparently not. The only thing I can say is that while you can do this, it's horrible practice for obvious reasons. — zfrisch, Mar 26 '18 at 16:16

score 0 · Answer 1 · answered Mar 26 '18 at 16:12

0

Try this as your function.

function textOccurrences() {
  var inputField1 = (document.getElementById("inputField1").value);
  var inputField2 = (document.getElementById("inputField2").value);
  var count = inputField1.split(inputField2).length - 1;
  document.getElementId("answer").value = inputField2 + "Occurs" + count + "times";
}

answered Mar 26 '18 at 16:12

Bibek Shah

419
4
19

1

While this code may answer the question, providing additional context regarding _how_ and/or _why_ it solves the problem would improve the answer's long-term value. – Andreas Mar 26 '18 at 16:13
Still has other issues, if OP just replaced the method, it is not going to work. – epascarello Mar 26 '18 at 16:13
this is an assignment where I need to use indexOf – Manny0 Mar 26 '18 at 16:15

treyhakanson · Answer 2 · 2018-03-26T16:25:26.257

0

You can use a regular expression:

function textOccurrences() {
  var inputField1 = (document.getElementById("inputField1").value);
  var inputField2 = (document.getElementById("inputField2").value);
  var re = new RegExp(inputField2, "g");
  var count = inputField1.match(re).length;
  document.getElementById("answer").value = inputField2 + " Occurs " + count + " times";
}

Note that in your code, you have said getElementId instead of getElementById, also contributing to the error.

edited Mar 26 '18 at 16:25

answered Mar 26 '18 at 16:17

treyhakanson

4,611
2
16
33

would the string method indexOf work at all in this particular situation? – Manny0 Mar 26 '18 at 16:31
You could, but you'd have to use `slice` to ignore the previous occurence during iterations since `indexOf` only gets the first occurrence. Possible but quite messy – treyhakanson Mar 26 '18 at 17:36
how would I do this? – Manny0 Mar 26 '18 at 18:22

score 0 · Answer 3 · answered Mar 26 '18 at 16:27

function textOccurrences() {
  var inputField1 = (document.getElementById("inputField1").value);
  var inputField2 = (document.getElementById("inputField2").value);
  var reg = new RegExp(inputField2,'g');
  document.getElementById("answer").value = inputField2 + "Occurs" + inputField1.match(reg).length + 
  "times";
}

You can try something like this

score 0 · Answer 4 · answered Mar 26 '18 at 16:34

you can use regex to match any occurence of you chosen letter and then count those matches and you have to syntax errors in your html and javascript
-it is onclick NOT onlick
-and it is getElementById NOT getElementId

here is you code after editing
Javascript

function textOccurrences() {
   var inputField1 = (document.getElementById("inputField1").value);
   var inputField2 = (document.getElementById("inputField2").value);
   console.log("hekasdlkjasd");
   var re = new RegExp(inputField2, "g");
   var count = inputField1.match(re).length;
   document.getElementById("answer").value = inputField2 + " Occurs " + count + " times";

}

Html

 <!DOCTYPE html>
 <html>
    <head>
        <title> Text Occurrences </title>
        <h1> Number of Character Occurrences</h1>
        <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
    </head>
 <body>
   <form>
       <p>Enter text: </p>
       <p> <input id="inputField1" type="text" /> </p>

       <p>Enter any character:</p>
       <p> <input id="inputField2" type="text" /> </p>
       <input type="button" value="Search" onclick="textOccurrences();" />
       </p>
       <p>Number of Occurrences:</p>
       <p><textarea id="answer"></textarea></p>
   </form>

 </body>
 </html>

I sort of understand now.Is there a way to use indexOf at all? — Manny0, Mar 26 '18 at 16:41
indexOf returns the index of the first occurrence of the letter for example `"asdasd".indexOf('d')` will return 2 the first occurrence of d is at position 2 — aa-Ahmed-aa, Mar 26 '18 at 16:44

count number of character occurrences in a sentence

4 Answers4