CoffeeScript String charCodeAt()用法及代码示例

描述

此方法返回一个数字，指示给定索引处字符的 Unicode 值。

Unicode 代码点的范围从 0 到 1,114,111。前 128 个 Unicode 代码点是 ASCII 字符编码的直接匹配。charCodeAt()始终返回小于 65,536 的值。

用法

下面给出的是 JavaScript 的 charCodeAt() 方法的语法。我们可以使用 CoffeeScript 代码中的相同方法。

string. charCodeAt(index)

它接受一个表示字符串索引的整数值，并返回字符串的指定索引处存在的字符的 Unicode 值。它返回NaN如果给定的索引不小于字符串长度的 0 到 1。

示例

下面的例子演示了使用charCodeAt()CoffeeScript 代码中的 JavaScript 方法。将此代码保存在具有名称的文件中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

打开command prompt并编译 .coffee 文件，如下所示。

c:\> coffee -c string_charcodeat.coffee

在编译时，它会为您提供以下 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);

现在，打开command prompt再次运行 CoffeeScript 文件，如下所示。

c:\> coffee string_charcodeat.coffee

在执行时，CoffeeScript 文件产生以下输出。

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