Home Web Front-end Front-end Q&A Usage of theNums in JavaScript

Usage of theNums in JavaScript

May 09, 2023 am 09:35 AM

theNums in JavaScript is a method for array processing. It is a built-in JavaScript function that converts each element in an array to a numeric type and returns a new array containing the numeric type.

In this article, we will introduce the usage, syntax and examples of theNums in detail to help you better understand and master this function.

Syntax

TheNums function has the following syntax:

array.theNums();

Among them, array represents the array to be converted. theNums function takes no arguments, converts each element in the array to a number and returns a new array containing the numeric type.

How to use

Using theNums function is very simple, just add .theNums() after the array to be converted. For example, we have an array of strings, and to convert each element in it to a numeric type, we can use the following code:

var arr = ["12", "34", "56"];
var numArr = arr.theNums();
console.log(numArr); // [12, 34, 56]
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In this example, we call theNums function of the array arr and will return The result is stored in the numArr variable. Because each element in arr is of type string, we convert them to numeric type using theNums function.

It should be noted that if an element in the array cannot be converted to a number, NaN will be returned. For example:

var arr = ["12", "34", "abc"];
var numArr = arr.theNums();
console.log(numArr); // [12, 34, NaN]
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In this example, since "abc" cannot be converted to a numeric type, NaN will be returned at the corresponding position in the new array.

Examples

Let’s look at a few practical examples to better understand the usage of theNums function.

1. Convert a string array to a numeric array

var strArr = ["12", "34", "56"];
var numArr = strArr.theNums();
console.log(numArr); // [12, 34, 56]
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In this example, we convert an array containing string type elements into a numeric type array.

2. Convert a mixed-type array to a pure numeric array

var mixArr = ["12", 34, "56", 78.9, "10.11"];
var numArr = mixArr.theNums();
console.log(numArr); // [12, 34, 56, 78.9, 10.11]
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In this example, we convert an array containing elements of different types into an array containing only numeric types. It should be noted that in string type elements, numbers and decimal points can be converted to numeric types.

3. Wrong usage

var arr = [12, 34, 56];
console.log(arr.theNums()); // arr.theNums is not a function
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In this example, we try to use theNums function on a numeric array, but because the numeric type array does not define this method, an error will be reported.

Summary

theNums is a convenience array processing method that converts the elements in the array to a numeric type and returns a new array containing the numbers. Its syntax is simple and easy to use. It should be noted that NaN will be returned when the elements in the array cannot be converted into numbers. Once you master the use of this method, you can easily perform operations such as array numerical operations.

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