ios 从iOS中的数据数组创建csv文件

Create csv file from array of data in iOS

提问by Prerna chavan

I want to write data from sql file to csv file. I have collected all data from sql file in an array and using for loop i am appending and writing data to .csv file. but it seems that it shows data in one line only it does not go to new line to create new row. I have used thisfor reference. This is my code :

我想将数据从 sql 文件写入 csv 文件。我已经从数组中的 sql 文件中收集了所有数据，并使用 for 循环将数据附加和写入 .csv 文件。但似乎它只在一行中显示数据，它不会转到新行来创建新行。我已经使用了这个作为参考。这是我的代码：

-(NSString *)dataFilePath { 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    return [documentsDirectory stringByAppendingPathComponent:@"myfile.csv"];
}

- (IBAction)saveAsFileAction:(id)sender {    
    if (![[NSFileManager defaultManager] fileExistsAtPath:[self dataFilePath]]) {
        [[NSFileManager defaultManager] createFileAtPath: [self dataFilePath] contents:nil attributes:nil];
        NSLog(@"Route creato");        
    }

    NSString *writeString;    
    for (int i=0; i<[dataArray count]; i++) {        
        writeString = [NSString stringWithFormat:@"%@, %@, %@, %@, %0.2f,",[[dataArray objectAtIndex:i]dates],[[dataArray objectAtIndex:i] time],[[dataArray objectAtIndex:i] category],[[dataArray objectAtIndex:i]place],[[dataArray objectAtIndex:i] amount]];        
        NSLog(@"writeString :%@",writeString);        
        NSFileHandle *handle;
        handle = [NSFileHandle fileHandleForWritingAtPath: [self dataFilePath] ]; 
        //say to handle where's the file fo write
        [handle truncateFileAtOffset:[handle seekToEndOfFile]]; 
        //position handle cursor to the end of file
        [handle writeData:[writeString dataUsingEncoding:NSUTF8StringEncoding]];      
    }    
}

回答by sosborn

This only writes one line because you rewrite the file every time you go through your loop. It is best to not writeDataon the file until the loop has completed. I would also use an NSMutableString like this:

这只会写一行，因为每次遍历循环时都会重写文件。最好writeData在循环完成之前不要打开文件。我也会像这样使用 NSMutableString：

- (IBAction)saveAsFileAction:(id)sender {

    if (![[NSFileManager defaultManager] fileExistsAtPath:[self dataFilePath]]) {
        [[NSFileManager defaultManager] createFileAtPath: [self dataFilePath] contents:nil attributes:nil];
        NSLog(@"Route creato");
    }

    NSMutableString *writeString = [NSMutableString stringWithCapacity:0]; //don't worry about the capacity, it will expand as necessary

    for (int i=0; i<[dataArray count]; i++) {
        writeString = [writeString appendString:[NSString stringWithFormat:@"%@, %@, %@, %@, %0.2f, \n",[[dataArray objectAtIndex:i]dates],[[dataArray objectAtIndex:i] time],[[dataArray objectAtIndex:i] category],[[dataArray objectAtIndex:i]place],[[dataArray objectAtIndex:i] amount]]]; //the \n will put a newline in
      }
    }

    //Moved this stuff out of the loop so that you write the complete string once and only once.
    NSLog(@"writeString :%@",writeString);

    NSFileHandle *handle;
    handle = [NSFileHandle fileHandleForWritingAtPath: [self dataFilePath] ]; 
    //say to handle where's the file fo write
    [handle truncateFileAtOffset:[handle seekToEndOfFile]]; 
    //position handle cursor to the end of file
    [handle writeData:[writeString dataUsingEncoding:NSUTF8StringEncoding]];
}    

回答by Pushkraj

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES); 
    NSString *documentsDir = [paths objectAtIndex:0];
    NSString *root = [documentsDir stringByAppendingPathComponent:@"customers.csv"];

    NSString *temp;

    temp = [NSString stringWithFormat:@"%@", [arrCustomersName objectAtIndex:0]];

    for (int i = 1; i < [arrCustomersName count]; i++) {

        temp = [temp stringByAppendingFormat:@", %@", [arrCustomersName objectAtIndex:i]];
    }

    [temp writeToFile:root atomically:YES encoding:NSUTF8StringEncoding error:NULL];

回答by Jaywant Khedkar

Try this it's working for me ,

试试这个它对我有用，

If any one want to create .csv file in swift 3

如果有人想在swift 3 中创建 .csv 文件

   // MARK: CSV file creating
    func creatCSV() -> Void {

    let fileName = "Tasks.csv"

    let path = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(fileName)
    var csvText = "Date,Task Name,Time Started,Time Ended\n"

    for task in taskArr {
        let newLine = "\(task.date),\(task.name),\(task.startTime),\(task.endTime)\n"
        csvText.append(newLine)
    }

    do {
        try csvText.write(to: path!, atomically: true, encoding: String.Encoding.utf8)
    } catch {
        print("Failed to create file")
        print("\(error)")
    }
    print(path ?? "not found")
   }
  }

For more details you can refer Detail Answer

有关更多详细信息，您可以参考详细答案

Hopes this will help to some one .

希望这将有助于某人。

回答by XLE_22

Instead of :

代替 ：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES); 
NSString *documentsDir = [paths objectAtIndex:0];
NSString *root = [documentsDir stringByAppendingPathComponent:@"customers.csv"];

... just write :

... 写就好了 ：

NSString *root = [NSHomeDirectory() stringByAppendingPathComponent:@"customers.csv"];

Exactly same result for only one short line of code. ;o)

只有一小行代码的结果完全相同。;o)

回答by iOS

 // For CSV File :
       NSMutableString *stringToWrite = [[NSMutableString alloc] init];
 [stringToWrite appendString:[NSString stringWithFormat:@"First Name,Last Name,Full Name,Phone Number, Email,Job, organizationName,Note\n\n"]];
 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
      for(int i = 0 ;i<[Contact count];i++)     {
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact objectAtIndex:i] valueForKey:@"firstName"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact objectAtIndex:i] valueForKey:@"lastName"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact valueForKey:@"userName"] objectAtIndex:i]]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact objectAtIndex:i] valueForKey:@"phoneNumber"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact objectAtIndex:i] valueForKey:@"emailAddress"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact objectAtIndex:i] valueForKey:@"jobTitle"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@,",[[Contact  objectAtIndex:i] valueForKey:@"organizationName"] ]];
           [stringToWrite appendString:[NSString stringWithFormat:@"%@\n",[[Contact objectAtIndex:i] valueForKey:@"note"] ]];
      }
      dispatch_async(dispatch_get_main_queue(), ^(void) {
           NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
           NSString *documentDirectory=[paths objectAtIndex:0];
           NSString *strBackupFileLocation = [NSString stringWithFormat:@"%@/%@", documentDirectory,@"ContactList.csv"];
           [stringToWrite writeToFile:strBackupFileLocation atomically:YES encoding:NSUTF8StringEncoding error:nil];
      });
 });