NSString 相关笔记

• 1.截取字符串

  NSString*string =@"sdfsfsfsAdfsdf";
  string = [string substringToIndex:7];//截取掉下标7之后的字符串
  NSLog(@"截取的值为：%@",string);
  [string substringFromIndex:2];//截取掉下标2之前的字符串
  NSLog(@"截取的值为：%@",string);

• 2.匹配字符串

  NSString*string =@"sdfsfsfsAdfsdf";
  NSRange range = [string rangeOfString:@"f"];//匹配得到的下标
  NSLog(@"rang:%@",NSStringFromRange(range));
  string = [string substringWithRange:range];//截取范围类的字符串
  NSLog(@"截取的值为：%@",string);

• 3.分隔字符串

  NSString*string =@"sdfsfsfsAdfsdf";
  
  //从字符A中分隔成2个元素的数组
  NSArray *array = [string componentsSeparatedByString:@"A"]; 
  
  //结果是adfsfsfs和dfsdf
  NSLog(@"array:%@",array); 
  
  NSRange range = [model.serviceName rangeOfString:@"★"];
  
  //字符串中没有★，名字不可能相同
  if (range.location==NSNotFound) return;
  
  /**截取*/
  NSString*codeString=[model.serviceName substringToIndex:range.location];

• 判断字符串中是否包含某个字符

 
  - (void)string:(NSString *)string containsStr:(NSString *)str{

   BOOL isContain=([string rangeOfString:str].location !=NSNotFound)?YES:NO;
   return isContain;
  }

• 从 URL中获取文件名以及后缀

     NSString* index=@"/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books/2013_50.zip";

  //对路径截取的9种操作

  NSLog(@"1=%@",[index lastPathComponent]);

  NSLog(@"2=%@",[index stringByDeletingLastPathComponent]);

  NSLog(@"3=%@",[index pathExtension]);

  NSLog(@"4=%@",[index stringByDeletingPathExtension]);

  NSLog(@"5=%@",[index stringByAbbreviatingWithTildeInPath]);

  NSLog(@"6=%@",[index stringByExpandingTildeInPath]);

  NSLog(@"7=%@",[index stringByStandardizingPath]);

  NSLog(@"8=%@",[index stringByResolvingSymlinksInPath]);

  NSLog(@"9=%@",[[index lastPathComponent] stringByDeletingPathExtension]);
  
  //对应结果
  
  1=2013_50.zip

  2=/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books

  3=zip

  4=/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books/2013_50

  5=~/Documents/DownLoad/books/2013_50.zip

  6=/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books/2013_50.zip

  7=/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books/2013_50.zip

  8=/Users/junzoo/Library/Application Support/iPhone Simulator/7.0.3/Applications/63925F20-AF97-4610-AF1C-B6B4157D1D92/Documents/DownLoad/books/2013_50.zip
 9=2013_50

• 字符串的转换

  
  1. NSString转化为UNICODE String：
  (NSString*)fname ＝ @“Test”;
  char fnameStr[10];
  memcpy(fnameStr, [fname cStringUsingEncoding:NSUnicodeStringEncoding], 2*([fname length]));

  //与strcpy相比，memcpy并不是遇到'\0'就结束，而是一定会拷贝完n个字节

  2. NSString 转化为 char *
  NSString * str＝ @“Test”;
  const char * a =[str UTF8String];

  3.char * 转化为 NSString
  NSString *str=[NSString stringWithCString  encoding:NSUTF8StringEncoding];

  4. char * 转化 NSData
  //方法一：
  char * a = (char*)malloc(sizeof(byte)*16);
  NSData *data = [NSData dataWithBytes: a   length:strlen(a)];
  //方法二：
  转换为NSString： - (id)initWithUTF8String:(const char *)bytes
  然后用NSString的 - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding

  5. NSData 转化 char *
  NSData data ；
  char* a=[data bytes];

  6. NSData 转化 NSString;
  NSData* data;
  NSString* aStr= ［NSString alloc] initWithData:data   encoding:NSASCIIStringEncoding];

  7. NSString 转化 NSData对象
  NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];

  8.NSString 转化 NSURL
  NSString *urlString=[@"http://www.google.com/search?client=safari&rls=en&q=搜索&ie=UTF-8&oe=UTF-8" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

  9.NSURL 转化 NSString
  NSURL *url=[NSURL URLWithString:urlString];
  NSString *s=[[url absoluteString] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

• NSString 文字编码转换

  NSURL *url = [NSURL URLWithString:urlStr];
  NSData *data = [NSData dataWithContentsOfURL:url];
  NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
  NSString *retStr = [[NSString alloc] initWithData:data encoding:enc];