How to reverse a string in javascript

How to reverse a string in javascript? This article will introduce to you how to reverse output a string in javascript, so that you can understand the method of reversing a string in javascript. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you. [Recommended related video tutorials: javascript tutorial]

1. Use a for loop with reduced connections

function reverse(s) {
  var str = '';
  for (var i = s.length - 1; i >= 0; i--)
    str += s[i];
  return str;
}
var str="hello";
str=reverse(str);
document.write("hello反转为： "+str);

Run:

Append each character entered to a new string in reverse order.

2. Use two arrays and use the increment/decrement for loop

function reverse(s) {
  var o = [];
  for (var i = s.length - 1, j = 0; i >= 0; i--, j++)
    o[j] = s[i];
  return o.join('');
}
var str="hello！";
str=reverse(str);
document.write("hello！反转为： "+str);

Output:

First create an empty array and iterate over the length of the string using up/down counters. Array positions use an up counter, where parsing in a string uses a down counter. Finally, the created arrays are concatenated into a string and returned.

3. Use array push and charAt incrementing for loop

function reverse(s) {
  var o = [];
  for (var i = 0, len = s.length; i <= len; i++)
    o.push(s.charAt(len - i));
  return o.join(&#39;&#39;);
}
var str="reverse";
str=reverse(str);
document.write("reverse 反转为： "+str);

Output:

This The example is a modification of the second example. Instead of using two counters we use an incrementing value that is subtracted from the total length parsed in the string. This calculated value determines the position of the next character to be pushed to the new array (use the 'push()' function instead of '[]'). Another difference from the previous example is that it uses the string 'charAt()' method instead of its array functionality.

4. Use javascript built-in function: reverse()

The reverse() method is used to reverse the order of elements in the array. The first array element becomes Last, the last array element becomes first; it converts the elements of the calling array object into place, mutates the array, and returns a reference to the array.

Note: reverse() method will change the original array but not create a new array.

function reverse(s) {
  return s.split('').reverse().join('');
}
var str="reverse()函数";
str=reverse(str);
document.write("reverse()函数 反转为： "+str);

Output:

First, it splits the string into a real array, then calls the 'reverse()' method, and finally returns the concatenated array .

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