JavaScript: Swap the first and last elements of a given array of integers
JavaScript Basic: Exercise-80 with Solution
Write a JavaScript program to swap the first and last elements of a given array of integers. The array length should be at least 1.
Pictorial Presentation:
Sample Solution:
HTML Code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>JavaScript program to swap the first and last elements of a given array of integers. The array length should be at least 1.</title>
</head>
<body>
</body>
</html>
JavaScript Code:
function swap(arra) {
[arra[0], arra[arra.length - 1]] = [arra[arra.length - 1], arra[0]];
return arra;
}
console.log(swap([1, 2, 3, 4]));
console.log(swap([0, 2, 1]));
console.log(swap([3]));
Sample Output:
[4,2,3,1] [1,2,0] [3]
Flowchart:
ES6 Version:
function swap(arra) {
[arra[0], arra[arra.length - 1]] = [arra[arra.length - 1], arra[0]];
return arra;
}
console.log(swap([1, 2, 3, 4]));
console.log(swap([0, 2, 1]));
console.log(swap([3]));
Live Demo:
See the Pen JavaScript - swap the first and last elements of a given array of integers - basic-ex-80 by w3resource (@w3resource) on CodePen.
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Previous: Write a JavaScript program to test if a given array of integers contains 30 and 40 twice.
Next: Write a JavaScript program to add two digits of a given positive integer of length two.
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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
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