CoffeeScript String charCodeAt()用法及代碼示例

描述

此方法返回一個數字，指示給定索引處字符的 Unicode 值。

Unicode 代碼點的範圍從 0 到 1,114,111。前 128 個 Unicode 代碼點是 ASCII 字符編碼的直接匹配。charCodeAt()始終返回小於 65,536 的值。

用法

下麵給出的是 JavaScript 的 charCodeAt() 方法的語法。我們可以使用 CoffeeScript 代碼中的相同方法。

string. charCodeAt(index)

它接受一個表示字符串索引的整數值，並返回字符串的指定索引處存在的字符的 Unicode 值。它返回NaN如果給定的索引不小於字符串長度的 0 到 1。

示例

下麵的例子演示了使用charCodeAt()CoffeeScript 代碼中的 JavaScript 方法。將此代碼保存在具有名稱的文件中string_charcodeat.coffee

str = "This is string"

console.log "The Unicode of the character at the index (0) is:" + str.charCodeAt 0 
console.log "The Unicode of the character at the index (1) is:" + str.charCodeAt 1 
console.log "The Unicode of the character at the index (2) is:" + str.charCodeAt 2 
console.log "The Unicode of the character at the index (3) is:" + str.charCodeAt 3 
console.log "The Unicode of the character at the index (4) is:" + str.charCodeAt 4 
console.log "The Unicode of the character at the index (5) is:" + str.charCodeAt 5

打開command prompt並編譯 .coffee 文件，如下所示。

c:\> coffee -c string_charcodeat.coffee

在編譯時，它會為您提供以下 JavaScript。

// Generated by CoffeeScript 1.10.0
(function() {
  var str;

  str = "This is string";

  console.log("The Unicode of the character at the index (0) is:" + str.charCodeAt(0));

  console.log("The Unicode of the character at the index (1) is:" + str.charCodeAt(1));

  console.log("The Unicode of the character at the index (2) is:" + str.charCodeAt(2));

  console.log("The Unicode of the character at the index (3) is:" + str.charCodeAt(3));

  console.log("The Unicode of the character at the index (4) is:" + str.charCodeAt(4));

  console.log("The Unicode of the character at the index (5) is:" + str.charCodeAt(5));

}).call(this);

現在，打開command prompt再次運行 CoffeeScript 文件，如下所示。

c:\> coffee string_charcodeat.coffee

在執行時，CoffeeScript 文件產生以下輸出。

The Unicode of the character at the index (0) is:84
The Unicode of the character at the index (1) is:104
The Unicode of the character at the index (2) is:105
The Unicode of the character at the index (3) is:115
The Unicode of the character at the index (4) is:32
The Unicode of the character at the index (5) is:105