JavaScript: Check a given string contains 2 to 4 numbers of a specified character

Last update on May 30 2022 10:00:16 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-35 with Solution

Write a JavaScript program to check a given string contains 2 to 4 numbers of a specified character.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JavaScript program to check a given string contains 2 to 4 numbers of a specified character.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function check_char(str1, char)
 {
  ctr = 0;
  for (let i = 0; i < str1.length; i++)
  {
    if ((str1.charAt(i) == char) && (i >= 1 && i <= 3))
    {
        ctr=1;
        break;
    }
   }
   if (ctr==1) return true;
   return false;
}
console.log(check_char("Python", "y"));
console.log(check_char("JavaScript", "a"));
console.log(check_char("Console", "o"));
console.log(check_char("Console", "C"));
console.log(check_char("Console", "e"));
console.log(check_char("JavaScript", "S"));

Sample Output:

true
true
true
false
false
false

Flowchart:

ES6 Version:

(function() {
    "use strict";
    function check_char(str1, char)
     {
      ctr = 0;
      for (let i = 0; i < str1.length; i++)
      {
        if ((str1.charAt(i) == char) && (i >= 1 && i <= 3))
        {
            ctr=1;
            break;
        }
       }
       if (ctr==1) return true;
       return false;
    }
    console.log(check_char("Python", "y"));
    console.log(check_char("JavaScript", "a"));
    console.log(check_char("Console", "o"));
    console.log(check_char("Console", "C"));
    console.log(check_char("Console", "e"));
    console.log(check_char("JavaScript", "S"));
}).call(this);

Live Demo:

See the Pen JavaScript: check a given string contains 2 to 4 numbers - basic-ex-35 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to check if the last digit of the three given positive integers is same.

JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04