How to convert string to integer in JavaScript without using parseInt() function?-JS Tutorial-php.cn

Table of Contents

Using the unary plus operator

Example

Using the Number() function

Use Math.floor() function

Using bitwise operators

Using the Math.ceil() function

Home

Web Front-end

JS Tutorial

How to convert string to integer in JavaScript without using parseInt() function?

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Aug 24, 2023 pm 09:57 PM

How to convert string to integer in JavaScript without using parseInt() function?

parseInt() is a built-in function in JavaScript that parses a string and returns an integer. However, sometimes we want to convert a string to an integer without using this function. In this article, we'll explore how to do this.

Using the unary plus operator

One way to convert a string to an integer is to use the unary plus operator. This operator converts its operand to a number. For example, the following program converts the string "123" to the number 123 -

Example 1

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result1"></div>
   <div id="result2"></div>
   <div id="result3"></div>
   <script>
      let str = "123";
      document.getElementById("result1").innerHTML = typeof str;
      let num = +str; // num = 123
      document.getElementById("result2").innerHTML = num;
      document.getElementById("result3").innerHTML = typeof num;
   </script>
</body>
</html>

Copy after login

Example 2

The unary plus operator can also be used to convert other values is a number. For example, it can convert a boolean value to a number as shown below −

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result"></div>
   <script>
      let bool = true;
      let num = +bool; // num = 1
      document.getElementById("result").innerHTML = num  
   </script>
</body>
</html>

Copy after login

Using the Number() function

Another way to convert a string into a number is by using the Number() function. This function takes in an argument and returns a number. For instance, the following code converts the string "123" into the number 123 −

Example 1

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result1"></div>
   <div id="result2"></div>
   <div id="result3"></div>
   <script>
      let str = "123";
      document.getElementById("result1").innerHTML = typeof str;
      let num = Number(str); // num = 123
      document.getElementById("result2").innerHTML = num;
      document.getElementById("result3").innerHTML = typeof num;
   </script>
</body>
</html>

Copy after login

Example 2

Number()The function can also be used to convert other values into numbers. For example, it can convert boolean values to numbers as shown below -

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result"></div>
   <script>
      let bool = false;
      let num = Number(bool); // num = 1
      document.getElementById("result").innerHTML = num    
   </script>
</body>
</html>

Copy after login

Use Math.floor() function

Math.floor()The function returns the largest integer less than or equal to the given number. This function can be used to convert a string to an integer.

Example

The following code converts the string "123" to the number 123−

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result1"></div>
   <div id="result2"></div>
   <div id="result3"></div>
   <script>
      let str = "123";
      document.getElementById("result1").innerHTML = typeof str;
      let num = Math.floor(str); // num = 123
      document.getElementById("result2").innerHTML = num;
      document.getElementById("result3").innerHTML = typeof num;
   </script>
</body>
</html>

Copy after login

In the above code, we first use the Number() function to convert the string " 123" converted to a number. We then pass this number to the Math.floor() function, which returns the integer 123.

Using bitwise operators

Bitwise operators are operators that operate on bit values. These operators can be used to convert strings to integers.

Example

The following code converts the string "765" to the number 765 −

<html>
<head>
   <title>Examples</title>
</head>
<body>
   <div id="result1"></div>
   <div id="result2"></div>
   <div id="result3"></div>
   <script>
      let str = "765";
      document.getElementById("result1").innerHTML = typeof str;
      let num = str|0;
      document.getElementById("result2").innerHTML = num;
      document.getElementById("result3").innerHTML = typeof num;
   </script>
</body>
</html>

Copy after login

In the above code, we use the bitwise OR operator (|) to convert the string "765" into a number. The bitwise OR operator converts its operands into 32-bit integers and then performs a bitwise OR operation on them. In this case, it converts the string "765" into the number 765.

Using the Math.ceil() function

The Math.ceil() function returns the smallest integer greater than or equal to a given number. This function can be used to convert a string into an integer.

Example

The following code converts the string "123" into the number 123 −

<!doctype html>
<html>
<head>  
   <title>Examples</title>
</head>
<body>  
   <div id=&#39;result1&#39;></div>  
   <div id=&#39;result2&#39;></div>  
   <div id=&#39;result3&#39;></div>  
   <script>      
      let str = &#39;123&#39;;      
      document.getElementById(&#39;result1&#39;).innerHTML ="String:" +str;      
      document.getElementById(&#39;result2&#39;).innerHTML = "Before:<br> Type: "+typeof str;      
      let num = Math.ceil(str); // num = 123            
      document.getElementById(&#39;result3&#39;).innerHTML = "After:<br> Type:"+typeof num;          
   </script>
</body>
</html>

Copy after login

In the above code, we first use Number( ) function converts the string "123" to a number. We then pass this number to the Math.ceil() function, which returns the integer 123.

There are several ways to convert a string to an integer without using the parseInt() function. These methods include using the unary plus operator, Number() function, Math.floor() function, and bitwise operators.

The above is the detailed content of How to convert string to integer in JavaScript without using parseInt() function?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress images for free

Clothoff.io

AI clothes remover

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Best Graphic Settings

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Assassin's Creed Shadows: Seashell Riddle Solution

2 weeks ago By DDD

R.E.P.O. How to Fix Audio if You Can't Hear Anyone

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

WWE 2K25: How To Unlock Everything In MyRise

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Where is the login entrance for gmail email?

7490

CakePHP Tutorial

1377

What is the format of the account name of steam

win11 activation key permanent

nyt connections hints and answers

Related knowledge

How do I create and publish my own JavaScript libraries? Mar 18, 2025 pm 03:12 PM

Article discusses creating, publishing, and maintaining JavaScript libraries, focusing on planning, development, testing, documentation, and promotion strategies.

How do I optimize JavaScript code for performance in the browser? Mar 18, 2025 pm 03:14 PM

The article discusses strategies for optimizing JavaScript performance in browsers, focusing on reducing execution time and minimizing impact on page load speed.

What should I do if I encounter garbled code printing for front-end thermal paper receipts? Apr 04, 2025 pm 02:42 PM

Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...

How do I debug JavaScript code effectively using browser developer tools? Mar 18, 2025 pm 03:16 PM

The article discusses effective JavaScript debugging using browser developer tools, focusing on setting breakpoints, using the console, and analyzing performance.

How do I use source maps to debug minified JavaScript code? Mar 18, 2025 pm 03:17 PM

The article explains how to use source maps to debug minified JavaScript by mapping it back to the original code. It discusses enabling source maps, setting breakpoints, and using tools like Chrome DevTools and Webpack.

Getting Started With Chart.js: Pie, Doughnut, and Bubble Charts Mar 15, 2025 am 09:19 AM

This tutorial will explain how to create pie, ring, and bubble charts using Chart.js. Previously, we have learned four chart types of Chart.js: line chart and bar chart (tutorial 2), as well as radar chart and polar region chart (tutorial 3). Create pie and ring charts Pie charts and ring charts are ideal for showing the proportions of a whole that is divided into different parts. For example, a pie chart can be used to show the percentage of male lions, female lions and young lions in a safari, or the percentage of votes that different candidates receive in the election. Pie charts are only suitable for comparing single parameters or datasets. It should be noted that the pie chart cannot draw entities with zero value because the angle of the fan in the pie chart depends on the numerical size of the data point. This means any entity with zero proportion

Who gets paid more Python or JavaScript? Apr 04, 2025 am 12:09 AM

There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.

TypeScript for Beginners, Part 2: Basic Data Types Mar 19, 2025 am 09:10 AM

Once you have mastered the entry-level TypeScript tutorial, you should be able to write your own code in an IDE that supports TypeScript and compile it into JavaScript. This tutorial will dive into various data types in TypeScript. JavaScript has seven data types: Null, Undefined, Boolean, Number, String, Symbol (introduced by ES6) and Object. TypeScript defines more types on this basis, and this tutorial will cover all of them in detail. Null data type Like JavaScript, null in TypeScript

See all articles