javascript integer type conversion

In JavaScript, integer type data can be converted in a variety of ways. This article will introduce how to convert integer types in JavaScript, including how to convert integers to strings, how to convert strings to integers, how to round integers to decimals with a specified number of digits, etc.

Convert an integer to a string

In JavaScript, the way to convert an integer to a string is through the toString() method. The toString() method can receive a parameter to specify the base (i.e. base) of the output string. The default is 10.

The following is an example:

var num = 123;
var str = num.toString(); // Convert integer to string
console.log(str ); // Output: "123"

By default, the toString() method converts the integer into a decimal string. If you need to convert the integer into a string in other bases, you can pass it in Specify the base number as a parameter. For example, the following code converts an integer to a binary string:

var num = 10;
var str = num.toString(2); // Convert an integer to a binary character String
console.log(str); // Output: "1010"

Similarly, the following code converts the integer into a hexadecimal string:

var num = 255 ;
var str = num.toString(16); // Convert integer to hexadecimal string
console.log(str); // Output: "ff"

will Convert a string to an integer

In JavaScript, the method to convert a string to an integer is through the parseInt() method. The parseInt() method can receive a string parameter and a base parameter, which is used to specify the string to be converted and the base number to be converted. If the base parameter is not specified, the default is 10.

The following is an example:

var str = "123";
var num = parseInt(str); // Convert string to integer
console.log( num); // Output: 123

If you need to convert the string into a binary, octal or hexadecimal integer, you can specify the base number when passing parameters. For example:

var str = "1010";
var num = parseInt(str, 2); // Convert binary string to integer
console.log(num); / / Output: 10

var str = "17";
var num = parseInt(str, 8); // Convert octal string to integer
console.log(num) ; // Output: 15

var str = "ff";
var num = parseInt(str, 16); // Convert hexadecimal string to integer
console.log( num); // Output: 255

It should be noted that if the string cannot be parsed into a number, NaN (Not a Number) will be returned. For example:

var str = "abc";
var num = parseInt(str);
console.log(num); // Output: NaN

Truncate the integer Rounding to a specified number of decimal places

In JavaScript, the method for rounding an integer to a specified number of decimal places is through the round() method of the Math object. The round() method can receive a numeric parameter to specify the number of decimal places to be rounded.

The following is an example:

var num = 3.1415926;
var roundNum = Math.round(num * 100) / 100; // Round num to 2 decimal places
console.log(roundNum); // Output: 3.14

It should be noted that when using the round() method to round, it will decide whether to go up or down based on the first digit of the decimal. included. If the first digit of the decimal is less than 5, it is rounded down; if it is greater than or equal to 5, it is rounded up.

Summary

In JavaScript, integer type conversion can be achieved through the toString() method and parseInt() method, and the integer can also be specified through the round() method of the Math object. Rounding of digits. In the actual development process, data processing can be completed more conveniently by selecting different conversion methods according to actual needs.

The above is the detailed content of javascript integer type conversion. For more information, please follow other related articles on the PHP Chinese website!