Objective C Unicode 字符比较 [英] Objective C unicode character comparisons

问题描述

unicode 比较是如何编码的?我需要完全按照下面的方式进行测试，检查字符串中的特定字母.下面的代码窒息:警告:指针和整数之间的比较

How are unicode comparisons coded? I need to test exactly as below, checking for specific letters in a string. The code below chokes: warning: comparison between pointer and integer

for (charIndex = 0; charIndex < [myString length]; charIndex++)
{
   unichar testChar = [myString characterAtIndex:charIndex];

     if (testChar == "A")  
       // do something
     if (testChar == "B")
      // do something
     if (testChar == "C")
      // do something
}

推荐答案

对于字符文字，使用单引号:

For char literals, use single quotes:

if (testChar == 'A') NSLog(@"It's an A");

或者用代码点编号表示字符:

Or represent the character using the code point number:

if (testChar == 0x1e01) NSLog(@"It's an A with a ring below");

编译器将双引号视为字符串，因此将A"构建为等效于 const char *(它会为您提供有关指针的错误消息).

The compiler sees double-quotes as a string, so builds "A" as equivalent to a const char * (which gives you there error message about the pointer).

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