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必须有一种比我想要的更简单的方法来进行简单的字符串操作。我有一种方法允许用户复制目录中的文件。如果他们在表格视图中选择它并按下克隆按钮，则会保存文件的副本，并且文件名将附加子字符串 Copy。如果 Copy 已经存在，那么我们需要迭代文件名并通过循环迭代附加文件名。例如;

<filename> Copy 1
<filename> Copy 2
until my other method return that the name is unique.

我需要检查传入的文件名的三个标准；它是否已经附加了“复制”是否已经附加了一个字符串数字如果是，获取数字的值将其迭代一并放回。

过了好一阵子，我只能想出这个：

//Tokenize the string
NSArray *filenameArray =[copyName componentsSeparatedByString:@" "];

//Make sure the name is unique
//Update the namesArray
[self montageNameList];
int i = 1;
for(NSString * name in self.montageNames){

    if([channelSetManager_ checkNoDuplicateName:self.montageNames forThisName:copyName]== YES){
        break;
    }else{

        if([[filenameArray lastObject]isEqualToString:@"Copy"]){

            //Just add a number to the end of the string
            copyName = [copyName stringByAppendingFormat:@" %d", i];

        }else if(([[filenameArray lastObject]intValue] > -1) && ([[filenameArray lastObject]intValue] < 100)){

            i = [[filenameArray lastObject]intValue]+1;
            NSInteger len = [[filenameArray lastObject]length]+1;
            copyName = [copyName substringToIndex:[copyName length] - len ];
            copyName = [copyName stringByAppendingFormat:@" %d",i];
        }

    }


}

这可行，但似乎不是正确的方法。任何意见是极大的赞赏。

4

1 回答 1

0

过去我使用创建了一个临时文件mkstemp()，然后将临时文件链接到永久文件，如果链接失败且文件存在，则尝试下一个文件名，重复直到链接成功，然后取消链接临时文件。

// Finds next available copy name and creates empty file as place holder
- (NSString *) createCopyFileWithBasename:(NSString *)baseName andSuffix:(NSString *)suffix
{
    char tmpFile[1024];
    char copyFile[1024];
    int  fd;
    int  count;

    // create unique temporary file
    snprintf(tmpFile, 1024, "%s.XXXXXXXX", [baseName UTF8String]);
    if ((fd = mkstemp(tmpFile)) == -1)
    {
       NSLog(@"mkstemp(): %s", strerror(errno));
       return(nil);
    };
    close(fd);

    // attempt to create empty file for file copy
    snprintf(copyFile, 1024, "%s Copy.%s", [baseName UTF8String], [suffix UTF8String]);
    switch(link(tmpFile, copyFile))
    {
       case EEXIST: // file exists, skip to next possible name
       break;

       case: 0: // excellent, we found an available file name
       unlink(tmpFile);
       return([NSString stringWithUTF8String:copyFile]);

       default:
       NSLog(@"link(): %s", strerror(errno));
       unlink(tmpFile);
       return(nil);
    };

    // loop through possible iterations of file copy's name
    for(count = 1; count < 1024; count++)
    {
       snprintf(copyFile, 1024, "%s Copy %i.s", [baseName UTF8String], count, [suffix UTF8String]);
       switch(link(tmpFile, copyFile))
       {
          case EEXIST: // file exists, skip to next possible name
          break;

          case: 0: // excellent, we found an available file name
          unlink(tmpFile);
          return([NSString stringWithUTF8String:copyFile]);

          default:
          NSLog(@"link(): %s", strerror(errno));
          unlink(tmpFile);
          return(nil);
       };
    };

   unlink(tmpFile);
   NSLog(@"link(): %s", strerror(errno));

   return(nil);
}

示例用法：

NSString copyFileName = [self createCopyFileWithBasename:@"My Data" andSuffix:@".txt"];
于 2012-06-06T01:14:07.417 回答