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Analysis of how to reverse numbers through javascript
- 藏色散人Original
- 2021-08-10 11:26:044064browse
"Reverse numbers" means outputting numbers in reverse order. For example, a number 12345, after reversal, is 54321; then in "Quickly reverse and output a positive integer through a PHP program" we explain how Reverse a number through PHP. Friends who are interested can learn about it~
The focus of this article is to explain how to reverse a number through javascript.
Without further ado, I will go directly to the code:
javascript to reverse the numbers:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
function reverse_a_number(n)
{
n = n + "";
return n.split("").reverse().join("");
}
console.log(reverse_a_number(32243));
</script>
</body>
</html>Then open the console to view the reversal result ：
In the above code, I gave an example number "32243", which is obviously reversed to "34223".
In the js code in the above example, you need to master 3 methods:
1.split() method: used to split a string into a string array, its syntax is " stringObject.split(separator,howmany)”;
parameters respectively represent:
separator，字符串或正则表达式，从该参数指定的地方分割 stringObject。 howmany，该参数可指定返回的数组的最大长度。如果设置了该参数，返回的子串不会多于这个参数指定的数组。如果没有设置该参数，整个字符串都会被分割，不考虑它的长度。
→Note: If an empty string ("") is used as separator, then each character in stringObject will be separated. String.split() performs the opposite operation of Array.join .
2.reverse() method: used to reverse the order of elements in an array, its syntax is "arrayObject.reverse()";
→Note: This method will change the original array but not create a new array.
3.join() method: used to put all the elements in the array into a string. The elements are separated by the specified delimiter. The syntax is "arrayObject. join(separator)"; its parameter separator specifies the separator to be used; if this parameter is omitted, a comma is used as the separator.
Finally, I would like to recommend "JavaScript Basics Tutorial" ~ Welcome everyone to learn ~
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