What is the javascript number conversion character function?

JavaScript is a widely used programming language that is used for web development, server-side programming, and various other application scenarios. In JavaScript, conversion between strings and numbers is a very common operation, and this conversion can be done through built-in functions.

JavaScript provides many functions for converting numbers to strings, such as toString(), toFixed(), and toPrecision() functions. These functions can be used to convert numbers to strings, and the output format can be specified as needed.

The toString() function is the most basic way to convert numbers to strings. This function can accept a parameter to specify the output base, for example:

var num = 10;
var str = num.toString();
console.log(str); // 输出 "10"

In the above example, the toString() function converts the integer 10 into the string "10". It can be seen that if the hexadecimal parameter is not specified, the default output is the string representation of the decimal value.

If you need to convert an integer into a string of other bases, you can do this by passing in base parameters in the toString() function:

var num = 255;
var str1 = num.toString(16); // 转换为16进制字符串
var str2 = num.toString(2); // 转换为2进制字符串
console.log(str1); // 输出 "ff"
console.log(str2); // 输出 "11111111"

In the above example, by converting the base Set the system parameters to 16 and 2 to convert the integer 255 into the hexadecimal string "ff" and the binary string "11111111" respectively.

In addition to the toString() function, JavaScript also provides toFixed() and toPrecision() functions to control the number of decimal places and the number of significant digits in the output.

The toFixed() function receives a parameter that specifies the number of digits to retain after the decimal point. For example:

var num = 1.23456789;
var str = num.toFixed(3);
console.log(str); // 输出 "1.235"

In the above example, the toFixed() function retains 3 digits after the decimal point and converts the result to the string "1.235". It should be noted that the output result is also a string, not a numeric type.

The toPrecision() function can control the number of significant digits output. For example:

var num = 123.456789;
var str = num.toPrecision(4);
console.log(str); // 输出 "123.5"

In the above example, the toPrecision() function limits the output result to 4 significant digits, and the result is "123.5".

It should be noted that conversion between numbers and strings can also be achieved in other ways, such as using the String() function:

var num = 123;
var str = String(num);
console.log(str); // 输出 "123"

Different from the toString() function, String() The function cannot specify hexadecimal parameters.

In short, there are many ways to convert numbers and strings in JavaScript, and you can choose the appropriate function according to your needs.

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