快速纠正NSString的顺序？

Question

有没有人知道改变现有NSString或NSMutableString字符顺序的现有方法？无论如何我都有一个解决方法,但如果有一个现有的方法,它会很棒.

例如,给定字符串@"HORSE",一个返回@"ORSEH",@"SORHE",@"ROHES"等的方法？

Answer 1

考虑以下代码:
.h文件:

@interface NSString (Scrambling)

+ (NSString *)scrambleString:(NSString *)toScramble;

@end

.m文件:

@implementation NSString (Scrambling)

+ (NSString *)scrambleString:(NSString *)toScramble {
   for (int i = 0; i < [toScramble length] * 15; i ++) {
      int pos = arc4random() % [toScramble length];
      int pos2 = arc4random() % ([toScramble length] - 1);
      char ch = [toScramble characterAtIndex:pos];
      NSString *before = [toScramble substringToIndex:pos];
      NSString *after = [toScramble substringFromIndex:pos + 1];
      NSString *temp = [before stringByAppendingString:after];
      before = [temp substringToIndex:pos2];
      after = [temp substringFromIndex:pos2];
      toScramble = [before stringByAppendingFormat:@"%c%@", ch, after];
   }
   return toScramble;
}

@end

不是最美丽的代码或执行,但完成工作.可能有一种(const char*)方法可以做到这一点,但这对我来说很好.快速测试显示在我的Mac上执行0.001021秒的长度.

用法:

NSString *scrambled = [NSString scrambleString:otherString];

代码改编自另一种语言/伪代码