foundation 框架 NSString常用总结(二)

以此作为NSString常用总结（一）的补充

 　　　　　NSString* str = [NSString stringWithFormat:@"I love programing! You, come here"];
         //字符串对象的大小写转换
         //转换为大写
         NSString* upStr = [str uppercaseString];
         NSLog(@"str = %@", str);
         NSLog(@"upStr = %@", upStr);
         //转换为小写
         NSString* lowerStr = [str lowercaseString];
         NSLog(@"lowerStr = %@", lowerStr);
         //转换成首字母大写
         NSString* newStr = [str capitalizedString];
         NSLog(@"newStr = %@", newStr);

         //字符串提取
         //指定位置到结尾：
         NSString* subStr = [str substringFromIndex:];
         NSLog(@"subStr = %@", subStr);
         //从指定位置提取指定长度(通过 NSRange)
         subStr = [str substringWithRange: NSMakeRange(, )];
          NSLog(@"subStr = %@", subStr);
         //开头到指定位置
         subStr = [str substringToIndex:];
          NSLog(@"subStr = %@", subStr);

         //字符串切割(componentsSeparatedByString:)方法
         //此方法根据传递的字符串进行分割，并将分割的结果以数组返回
         NSArray* strArr = [str componentsSeparatedByString:@" "];
         for (id str in strArr) {
             NSLog(@"%@", str);
         }
         //拼接数组中得字符串(按指定字符串)
         NSString* myStr = [strArr componentsJoinedByString:@"__"];
         NSLog(@"mystr = %@", myStr);
         //根据传递进来的NSCharacterSet集合进行分割(示例中包含逗号“,”和空格“ ”)
         strArr = [str componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@", "]];
         for (id str in strArr) {
             NSLog(@"%@", str);
         }