The editor of Downcodes will take you to understand the JavaScript calculation method of Chinese character location codes. Chinese character location code is an encoding method in early Chinese processing systems. Although UTF-8 encoding is more popular today, understanding the calculation principle of location code can help to deeply understand character encoding. This article will explain in detail how to calculate the location code of Chinese characters through pure JavaScript code, and provide complete code examples and precautions to help you easily master this knowledge point.
The location code of Chinese characters is a way of encoding Chinese characters in computer systems, and is usually used in early Chinese processing systems. In the modern Internet, UTF-8 encoding is more versatile and flexible. If you want to use pure JavaScript code to find the location code of a Chinese character, you can do it by calculating the offset value of the Chinese character relative to the national standard code.
In JavaScript, to obtain the location code of a Chinese character, you need to convert the Chinese character into its encoded value, and then use some arithmetic operations to obtain the location code. The calculation formula of the location code can be briefly described as: the national standard code of Chinese characters -0xA0 is used to obtain the row and column values, and then converted to decimal to obtain the location code.
First of all, obtaining the character encoding of Chinese characters is the prerequisite for calculating the location code. In JavaScript, we can use the charCodeAt() method to get the encoding value of a character.
function getCharCode(ch) {
if (typeof ch === 'string' && ch.length === 1) {
return ch.charCodeAt(0);
} else {
throw new Error('Input must be a single character.');
}
}
This function passes in a single character, checks the input to ensure it is a single Chinese character, and then returns the Unicode encoding of the Chinese character.
After obtaining the code, the location code of the Chinese character can be obtained according to the calculation rules of the location code.
function computeQuWeiCode(ch) {
const charCode = getCharCode(ch);
//The row bytes and column bytes of the national standard code are the character encoding minus 0xA0
const OFFSET = 0xA0;
const rowByte = Math.floor((charCode - OFFSET) / 256);
const colByte = (charCode - OFFSET) % 256;
// Convert to location code format
return { row: rowByte, col: colByte };
}
This function rounds down the character encoding through Math.floor to obtain the row bytes of the national standard code, and the column bytes are obtained by taking the remainder.
The calculated location code needs to be presented in an easy-to-read way:
function formatQuWeiCode(quWeiCode) {
// The location code is usually displayed in four digits, and the missing part is filled with 0
return ${quWeiCode.row.toString().padStart(2, '0')}${quWeiCode.col.toString().padStart(2, '0')};
}
This function accepts the output result of the computeQuWeiCode() function and formats the row and column values into a four-digit location code, with less than two digits padded with 0s.
Now we can integrate the above steps into a complete function to find the location code of any Chinese character:
function getQuWeiCodeOfChineseChar(ch) {
// Get character encoding
const charCode = getCharCode(ch);
// Calculate area code
const quWeiCode = computeQuWeiCode(ch);
//Format output
return formatQuWeiCode(quWeiCode);
}
// Example usage:
const quWeiCode = getQuWeiCodeOfChineseChar('中');
console.log(quWeiCode); // The location code of Chinese characters will be output here, such as "4956"
This function can provide you with the location code of Chinese characters. It is worth noting that the location code is the encoding method under the GB2312 standard. For characters encoded by other standards (such as GB18030, GBK, etc.) or Unicode, the calculation method may need to be adjusted. Moreover, most modern computer systems and network communications use Unicode encoding, so you need to pay attention to encoding compatibility issues when using it.
In addition, there are some constraints and limitations in location code calculation:
The input must be GB2312 encoded Chinese characters. JavaScript uses Unicode character encoding in modern browsers. If you need to handle non-standard Chinese character encoding, a more complex mapping method may be required. Processing location codes directly in JavaScript is retro and not suitable for all modern Chinese character processing needs.Calculations using location codes are suitable for maintenance of older systems or for text processing in specific situations. But currently, UTF-8 encoding has better versatility and compatibility, so it is the preferred encoding standard for Chinese processing on the modern Internet and application software.
In daily development work, you may rarely need to deal with location codes directly, but understanding its principles can deepen your understanding of character encoding and have a basic understanding of early Chinese information processing technology.
1. How to get the location code from Chinese characters using pure JavaScript code?
In JavaScript, you can use the charCodeAt() method to obtain the Unicode encoding of a character. For Chinese characters, the first two digits of the Unicode encoding represent its location code.
The following is a sample code that shows how to use pure JavaScript code to obtain the location code from Chinese characters:
function getZoneCode(character) { var unicode = character.charCodeAt(0).toString(16); //Convert characters to Unicode-encoded hexadecimal strings var zoneCode = unicode.slice(0, 2); // Get the first two digits as the zone code return zoneCode;}var chineseCharacter = 'you'; //To get the Chinese character of the zone code var zoneCode = getZoneCode(chineseCharacter); //Call the function to get the zone code console.log('Zone code: ' + zoneCode);By calling the getZoneCode() function and passing in the Chinese character to obtain the zone code as a parameter, the zone code of the Chinese character will eventually be output on the console.
2. How to use pure JavaScript code to find the location codes of Chinese characters in batches?
If you need to obtain the location codes of multiple Chinese characters at once, you can modify the above code, use a loop to traverse the Chinese character array, and then store the location code of each Chinese character in a new array. Here is the modified example code:
function getZoneCodes(characters) { var zoneCodes = []; for (var i = 0; i < characters.length; i++) { var unicode = characters[i].charCodeAt(0).toString(16); var zoneCode = unicode .slice(0, 2); zoneCodes.push(zoneCode); } return zoneCodes;}var chineseCharacters = ['you', '好', '世', '世界']; //To obtain the Chinese character array of zone codes var zoneCodes = getZoneCodes(chineseCharacters);console.log('Zone code:' + zoneCodes.join(', '));After running the above code, the location codes of all Chinese characters will be output on the console, separated by commas.
3. How to convert the location code back to Chinese characters using pure JavaScript code?
If you have an area code and want to convert it back to the corresponding Chinese character, you can use the String.fromCharCode() method. Here is sample code:
function getCharacter(zoneCode) { var unicode = zoneCode + '000'; var character = String.fromCharCode(parseInt(unicode, 16)); return character;}var zoneCode = '4f60'; //Zone code to be converted to Chinese characters var character = getCharacter(zoneCode);console.log('Chinese character: ' + character);In the above code, the getCharacter() function receives a location code as a parameter, converts it to Unicode encoding, and then uses String.fromCharCode() to convert it to the corresponding Chinese character. After running the code, the Chinese characters corresponding to the location code will be output on the console.
Hope the above answers are helpful to you!
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