//1.多个数据拼接成一个字符串        int year = 1988;        int month = 4;        int day = 15;        NSString * date = [NSString stringWithFormat:@"%d年%d月%d日",year,month,day];        NSLog(@"date %@",date);        NSString * address = @"昌平区,金燕龙";        NSString * dateAndAddrss = [NSString stringWithFormat:@"%@地址:%@",date,address];        NSLog(@"dateAndAddress %@",dateAndAddrss);                //2.字符串的末尾追加新的字符        NSString * str1 = @"www.";        NSString * str2 = [str1 stringByAppendingString:@"itcast.cn"];        NSLog(@"str2 %@ str1 %@",str2,str1);                //3.在制定的范围追加字符串        NSString * str3 = @"www.cn";        NSRange range = {4,0};        // 4 location代表的时从哪个索引开始插入,length 代表的意思可以覆盖几个字符        NSString * str4 = [str3 stringByReplacingCharactersInRange:range withString:@"itcast."];        NSLog(@"str4 %@",str4);                //4.使用新的字符,替换原有的字符        NSString * str5 = @"www.itcast.cn";        NSString * str6 = [str5 stringByReplacingOccurrencesOfString:@"w" withString:@"a"];        NSLog(@"str6 %@",str6);                //5.在字符串中删除特定的某些字符 胡汉三 hhs        NSString * str7 = @"www---.itcatst.--cn";        NSString * str8 = [str7 stringByReplacingOccurrencesOfString:@"-" withString:@""];        NSLog(@"str8 %@",str8);                //6.去掉字符串中的空格        NSString * str9 = @"www  .itcat  .cn";        NSString * str10 = [str9 stringByReplacingOccurrencesOfString:@" " withString:@""];        NSLog(@"str10 %@",str10);