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

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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Previous: Write a JavaScript program to find the larger number from the two given positive integers, the two numbers are in the range 40..60 inclusive.
Next: Write a JavaScript program to check if the last digit of the three given positive integers is same.

What is the difficulty level of this exercise?



JavaScript: Tips of the Day

Parameter's value

function getItems(fruitList, ...args, favoriteFruit) {
  return [...fruitList, ...args, favoriteFruit]
}

getItems(["banana", "apple"], "pear", "orange")

...args is a rest parameter. The rest parameter's value is an array containing all remaining arguments, and can only be the last parameter! In this example, the rest parameter was the second parameter. This is not possible, and will throw a syntax error.

function getItems(fruitList, favoriteFruit, ...args) {
  return [...fruitList, ...args, favoriteFruit];
}


getItems(['banana', 'apple'], 'pear', 'orange');
The above example works. This returns the array [ 'banana', 'apple', 'orange', 'pear' ].

Ref: https://bit.ly/3jFRBje