JavaScript中十进制转ASCII及表格特殊记录转正常单词方法咨询

Hey there, let's tackle your two JavaScript questions one by one with practical, actionable code examples:

1. Converting Decimal Numbers to ASCII Characters #

In JavaScript, the go-to method for this is String.fromCharCode(). It takes one or more decimal values (corresponding to ASCII code points) and returns the associated character(s).

Basic Usage #

• Single character:

  const decimal = 65;
  const asciiChar = String.fromCharCode(decimal);
  console.log(asciiChar); // Output: "A"
  

• Multiple characters (pass multiple decimal values):

  const decimals = [72, 101, 108, 108, 111];
  const asciiString = String.fromCharCode(...decimals);
  console.log(asciiString); // Output: "Hello"
  

Quick Note #

• This works for standard ASCII (0-127) and extended ASCII (128-255) values. For Unicode code points beyond 255, you'd use String.fromCodePoint() instead, but that's outside the core ASCII scope.

2. Converting Special Formatted Words to Normal Words #

Since "special formatted" can cover a few common scenarios (full-width characters, messy casing, embedded symbols, HTML entities, etc.), I'll break down the most frequent cases with tailored solutions:

Scenario 1: Full-Width to Half-Width Characters #

If your words use full-width (East Asian style) letters/numbers, use this function to convert them:

function fullWidthToHalfWidth(str) {
  return str.replace(/[\uFF01-\uFF5E]/g, char => {
    // Shift full-width code point to half-width equivalent
    return String.fromCharCode(char.charCodeAt(0) - 0xFEE0);
  }).replace(/\uFF00/g, ' '); // Handle full-width space separately
}

// Example usage:
const fullWidthStr = "Ｈｅｌｌｏ！１２３";
console.log(fullWidthToHalfWidth(fullWidthStr)); // Output: "Hello! 123"

Scenario 2: Clean Up Unwanted Special Symbols #

To strip irrelevant symbols and keep only letters, numbers, spaces, and basic punctuation:

function cleanSpecialSymbols(str) {
  // Adjust the regex character set based on what you want to retain
  return str.replace(/[^a-zA-Z0-9\s.,!?]/g, '');
}

// Example usage:
const messyStr = "H@e#l$l%o^1&2*3";
console.log(cleanSpecialSymbols(messyStr)); // Output: "Hello 123"

Scenario 3: Fix Inconsistent Casing #

If words have random capitalization, use these snippets to normalize:

• Make first letter of each word uppercase, rest lowercase:

  function normalizeCasing(str) {
    return str.toLowerCase().replace(/\b\w/g, char => char.toUpperCase());
  }
  
  // Example usage:
  const messyCaseStr = "hElLo wOrLd";
  console.log(normalizeCasing(messyCaseStr)); // Output: "Hello World"
  

Scenario 4: Decode HTML Entities #

If your words are encoded with HTML entities (like & for &), use this safe method:

function decodeHtmlEntities(str) {
  const parser = new DOMParser();
  const doc = parser.parseFromString(str, "text/html");
  return doc.body.textContent;
}

// Example usage:
const encodedStr = "H&e&l&l&o";
console.log(decodeHtmlEntities(encodedStr)); // Output: "H&e&l&l&o"

Pick the scenario that matches your specific "special format" issue, or combine functions if you need to fix multiple problems at once!

内容的提问来源于stack exchange，提问作者Kai Tera