xcode 如何将核心数据导出到 CSV
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how to export Core Data to CSV
提问by Desmond
I will like to use CHCSVParserto export my Core data to CSV. I know how to get all the value from entity, but I don't know how to write to CSV.
我想用来CHCSVParser将我的核心数据导出到 CSV。我知道如何从实体中获取所有值，但我不知道如何写入 CSV。
Can anybody teach me how to write to CSV with CHCSVParser?
有人可以教我如何用 CSV 写入CHCSVParser吗？
// Test listing all Infos from the store
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:@"NoteLog" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
for (NoteLog *noteInfo in fetchedObjects) {
NSLog(@"Name: %@", noteInfo.city );
NSLog(@"Name: %@", noteInfo.country);
NSLog(@"Name: %@", noteInfo.datetime);
NSLog(@"Name: %@", noteInfo.notelatitude);
NSLog(@"Name: %@", noteInfo.notelongtitude);
NSLog(@"Name: %@", noteInfo.state);
NSLog(@"Name: %@", noteInfo.text);
}
回答by Ryan Poolos
A CHCSVWriterhas several methods for constructing CSV files:
ACHCSVWriter有几种构造CSV文件的方法：
-writeField:accepts an object and writes its -description (after being properly escaped) out to the CSV file. It will also write field seperator (,) if necessary. You may pass an empty string (@"") or nil to write an empty field.
-writeField:接受一个对象并将其 -description（在正确转义后）写入 CSV 文件。如有必要，它还将写入字段分隔符 (,)。您可以传递一个空字符串 (@"") 或 nil 来写入一个空字段。
-writeFields:accepts a comma-delimited and nil-terminated list of objects and sends each one to -writeField:.
-writeFields:接受以逗号分隔且以 nil 结尾的对象列表，并将每个对象发送到 -writeField:。
-writeLineis used to terminate the current CSV line. If you do not invoke -writeLine, then all of your CSV fields will be on a single line.
-writeLine用于终止当前的 CSV 行。如果不调用 -writeLine，则所有 CSV 字段都将位于一行中。
-writeLineOfFields:accepts a comma-delimited and nil-terminated list of objects, sends each one to -writeField:, and then invokes -writeLine.
-writeLineOfFields:接受以逗号分隔且以 nil 结尾的对象列表，将每个对象发送到 -writeField:，然后调用 -writeLine。
-writeLineWithFields:accepts an array of objects, sends each one to -writeField:, and then invokes -writeLine.
-writeLineWithFields:接受一组对象，将每个对象发送到 -writeField:，然后调用 -writeLine。
-writeCommentLine:accepts a string and writes it out to the file as a CSV-style comment.
-writeCommentLine:接受一个字符串并将其作为 CSV 样式的注释写入文件。
In addition to writing to a file, CHCSVWritercan be initialized for writing directly to an NSString.
除了写入文件之外，CHCSVWriter还可以初始化为直接写入NSString.
Something Like this should work for you.
像这样的东西应该适合你。
CHCSVWriter *writer = [[CHCSVWriter alloc] initForWritingToString];
for (NoteLog *noteInfo in fetchedObjects) {
[writer writeLineOfFields:noteInfo.city, noteInfo.country, noteInfo.datetime, noteInfo.notelatitude, noteInfo.notelongtitude, noteInfo.state, noteInfo.text, nil];
}
NSLog(@"My CSV File: %@",writer.stringValue);
回答by Mic Fok
The answer above seems to be deprecated, the author replaced the method with another it seem. This worked for me, hope it helps:
上面的答案似乎已被弃用，作者似乎用另一种方法替换了该方法。这对我有用，希望它有帮助：
NSOutputStream *stream = [[NSOutputStream alloc] initToMemory];
CHCSVWriter *writer = [[CHCSVWriter alloc] initWithOutputStream:stream encoding:NSUTF8StringEncoding delimiter:','];
for (Type *instance in fetchedResults) {
[writer writeLineOfFields:@[instance.propertyA, instance.B]];
}
[writer closeStream];
NSData *buffer = [stream propertyForKey:NSStreamDataWrittenToMemoryStreamKey];
NSString *output = [[NSString alloc] initWithData:buffer encoding:NSUTF8StringEncoding];
