在 Core Data 中加载 csv 文件
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【中文标题】在 Core Data 中加载 csv 文件【英文标题】：Loading csv file in Core Data 【发布时间】：2013-09-26 21:52:02 【问题描述】：第一次运行应用程序时，我试图在核心数据中加载一个 csv 文件。在此处（What is the fastest way to load a large CSV file into core data）找到的关于 *** 的另一篇文章中，我发现了如何做到这一点。
我在我的控制器中使用与提供的函数相同的代码：populateDB，如果之前从未加载过数据（第一次运行），则调用该函数。但是，xcode 给了我一个错误：
No visible @interface for ...Controller declares the selector persistentStoreCoordinator.
函数是：
-(void)populateDB
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
NSManagedObjectContext *context;
if (coordinator != nil)
context = [[NSManagedObjectContext alloc] init];
[context setPersistentStoreCoordinator:coordinator];
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"input" ofType:@"txt"];
if (filePath)
NSString * myText = [[NSString alloc]
initWithContentsOfFile:filePath
encoding:NSUTF8StringEncoding
error:nil];
if (myText)
__block int count = 0;
[myText enumerateLinesUsingBlock:^(NSString * line, BOOL * stop)
line=[line stringByReplacingOccurrencesOfString:@"\t" withString:@" "];
NSArray *lineComponents=[line componentsSeparatedByString:@" "];
if(lineComponents)
if([lineComponents count]==3)
float f=[[lineComponents objectAtIndex:0] floatValue];
NSNumber *number=[NSNumber numberWithFloat:f];
NSString *string1=[lineComponents objectAtIndex:1];
NSString *string2=[lineComponents objectAtIndex:2];
NSManagedObject *object=[NSEntityDescription insertNewObjectForEntityForName:@"Bigram" inManagedObjectContext:context];
[object setValue:number forKey:@"number"];
[object setValue:string1 forKey:@"string1"];
[object setValue:string2 forKey:@"string2"];
NSError *error;
count++;
if(count>=1000)
if (![context save:&error])
NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
count=0;
];
NSLog(@"done importing");
NSError *error;
if (![context save:&error])
NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
我在离开 3 年后再次拿起 ios，我之前从未深入研究过 SDK 的这一部分。我将不胜感激任何有关此问题的帮助...
【问题讨论】：
感谢@GabrielePetronella 在这里的编辑/课程:) 我们又见面了 :) 只是简短的评论，因为我们在这里：您应该发布答案，而不是在问题中包含答案。如果您认为这是最合适的答案，您也可以接受（2 天后） 我应该继续更新吗？ 干得好，现在格式完美，人们更容易找到答案。 【参考方案1】：下面的代码向您展示了一个在 Core Data 中加载 csv 文件的示例，该示例使用 Matt Gallagher 的 CSVParser.h 类并假设一个实体 MyEntity
// CSV File input.csv and not input.txt separate by space @" "
CSVParser *csvParser = [[CSVParser alloc] initWithContentOfFile:[NSBundle mainBundle] pathForResource:@"input" ofType:@"csv" separator:@" "];
// Array with all your data from CSV
NSArray *data = [csvParser parseFile];
// Your entity from Core Data
MyEntity *myEntity = nil;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
for (NSDictionary *dic in data)
fetchRequest.entity = [NSEntityDescription entityForName:@"MyEntity" inManagedObjectContext:context];
if (!entity)
entity = [NSEntityDescription insertNewObjectForEntityForName:@"MyEntity"
inManagedObjectContext:context];
[entity setValue:number forKey:@"number"];
[entity setValue:string1 forKey:@"string1"];
[entity setValue:string2 forKey:@"string2"];
// Save the context
[managedObjectContext save:nil];
CVSParser.h 使用 ARC：
//
// CSVParser.h
// CSVImporter
//
// Created by Matt Gallagher on 2009/11/30.
// Copyright 2009 Matt Gallagher. All rights reserved.
//
// Permission is given to use this source code file, free of charge, in any
// project, commercial or otherwise, entirely at your risk, with the condition
// that any redistribution (in part or whole) of source code must retain
// this copyright and permission notice. Attribution in compiled projects is
// appreciated but not required.
//
// Source : http://cocoawithlove.com/2009/11/writing-parser-using-nsscanner-csv.html
@interface CSVParser : NSObject
NSString *csvString;
NSString *separator;
NSScanner *scanner;
BOOL hasHeader;
NSMutableArray *fieldNames;
id receiver;
SEL receiverSelector;
NSCharacterSet *endTextCharacterSet;
BOOL separatorIsSingleChar;
- (id)initWithString:(NSString *)aCSVString
separator:(NSString *)aSeparatorString;
- (id)initWithContentOfFile:(NSString *)aPath
separator:(NSString *)aSeparatorString;
- (id)initWithString:(NSString *)aCSVString
separator:(NSString *)aSeparatorString
hasHeader:(BOOL)header
fieldNames:(NSArray *)names;
- (id)initWithContentOfFile:(NSString *)aPath
separator:(NSString *)aSeparatorString
hasHeader:(BOOL)header
fieldNames:(NSArray *)names;
- (NSArray *)arrayOfParsedRows;
- (void)parseRowsForReceiver:(id)aReceiver selector:(SEL)aSelector;
- (NSArray *)parseFile;
- (NSMutableArray *)parseHeader;
- (NSDictionary *)parseRecord;
- (NSString *)parseName;
- (NSString *)parseField;
- (NSString *)parseEscaped;
- (NSString *)parseNonEscaped;
- (NSString *)parseDoubleQuote;
- (NSString *)parseSeparator;
- (NSString *)parseLineSeparator;
- (NSString *)parseTwoDoubleQuotes;
- (NSString *)parseTextData;
@end
CVSParser.m 使用 ARC：
//
// CSVParser.m
// CSVImporter
//
// Created by Matt Gallagher on 2009/11/30.
// Copyright 2009 Matt Gallagher. All rights reserved.
//
// Permission is given to use this source code file, free of charge, in any
// project, commercial or otherwise, entirely at your risk, with the condition
// that any redistribution (in part or whole) of source code must retain
// this copyright and permission notice. Attribution in compiled projects is
// appreciated but not required.
//
#import "CSVParser.h"
@implementation CSVParser
//
// initWithString:separator:hasHeader:fieldNames:
//
// Parameters:
// aCSVString - the string that will be parsed
// aSeparatorString - the separator (normally "," or "\t")
// header - if YES, treats the first row as a list of field names
// names - a list of field names (will have no effect if header is YES)
//
// returns the initialized object (nil on failure)
//
- (id)initWithString:(NSString *)aCSVString
separator:(NSString *)aSeparatorString
hasHeader:(BOOL)header
fieldNames:(NSArray *)names
self = [super init];
if (self)
csvString = [aCSVString retain];
separator = [aSeparatorString retain];
NSAssert([separator length] > 0 &&
[separator rangeOfString:@"\""].location == NSNotFound &&
[separator rangeOfCharacterFromSet:[NSCharacterSet newlineCharacterSet]].location == NSNotFound,
@"CSV separator string must not be empty and must not contain the double quote character or newline characters.");
NSMutableCharacterSet *endTextMutableCharacterSet =
[[NSCharacterSet newlineCharacterSet] mutableCopy];
[endTextMutableCharacterSet addCharactersInString:@"\""];
[endTextMutableCharacterSet addCharactersInString:[separator substringToIndex:1]];
endTextCharacterSet = endTextMutableCharacterSet;
if ([separator length] == 1)
separatorIsSingleChar = YES;
hasHeader = header;
fieldNames = [names mutableCopy];
return self;
- (id)initWithString:(NSString *)aCSVString
separator:(NSString *)aSeparatorString
return [self initWithString:aCSVString
separator:aSeparatorString
hasHeader:YES
fieldNames:nil];
- (id)initWithContentOfFile:(NSString *)aPath
separator:(NSString *)aSeparatorString
return [self initWithString:[NSString stringWithContentsOfFile:aPath
encoding:NSUTF8StringEncoding
error:nil]
separator:aSeparatorString];
- (id)initWithContentOfFile:(NSString *)aPath
separator:(NSString *)aSeparatorString
hasHeader:(BOOL)header
fieldNames:(NSArray *)names
return [self initWithString:[NSString stringWithContentsOfFile:aPath
encoding:NSUTF8StringEncoding
error:nil]
separator:aSeparatorString
hasHeader:header
fieldNames:names];
//
// dealloc
//
// Releases instance memory.
//
- (void)dealloc
[csvString release];
[separator release];
[fieldNames release];
[endTextCharacterSet release];
[super dealloc];
//
// arrayOfParsedRows
//
// Performs a parsing of the csvString, returning the entire result.
//
// returns the array of all parsed row records
//
- (NSArray *)arrayOfParsedRows
scanner = [[NSScanner alloc] initWithString:csvString];
[scanner setCharactersToBeSkipped:[[[NSCharacterSet alloc] init] autorelease]];
NSArray *result = [self parseFile];
[scanner release];
scanner = nil;
return result;
//
// parseRowsForReceiver:selector:
//
// Performs a parsing of the csvString, sending the entries, 1 row at a time,
// to the receiver.
//
// Parameters:
// aReceiver - the target that will receive each row as it is parsed
// aSelector - the selector that will receive each row as it is parsed
// (should be a method that takes a single NSDictionary argument)
//
- (void)parseRowsForReceiver:(id)aReceiver selector:(SEL)aSelector
scanner = [[NSScanner alloc] initWithString:csvString];
[scanner setCharactersToBeSkipped:[[[NSCharacterSet alloc] init] autorelease]];
receiver = [aReceiver retain];
receiverSelector = aSelector;
[self parseFile];
[scanner release];
scanner = nil;
[receiver release];
receiver = nil;
//
// parseFile
//
// Attempts to parse a file from the current scan location.
//
// returns the parsed results if successful and receiver is nil, otherwise
// returns nil when done or on failure.
//
- (NSArray *)parseFile
scanner = [[NSScanner alloc] initWithString:csvString];
[scanner setCharactersToBeSkipped:[[[NSCharacterSet alloc] init] autorelease]];
if (hasHeader)
if (fieldNames)
[fieldNames release];
fieldNames = [[self parseHeader] retain];
if (!fieldNames || ![self parseLineSeparator])
return nil;
NSMutableArray *records = nil;
if (!receiver)
records = [NSMutableArray array];
NSDictionary *record = [[self parseRecord] retain];
if (!record)
return nil;
while (record)
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
if (receiver)
[receiver performSelector:receiverSelector withObject:record];
else
[records addObject:record];
[record release];
if (![self parseLineSeparator])
break;
record = [[self parseRecord] retain];
[pool drain];
[scanner release];
scanner = nil;
return records;
//
// parseHeader
//
// Attempts to parse a header row from the current scan location.
//
// returns the array of parsed field names or nil on parse failure.
//
- (NSMutableArray *)parseHeader
NSString *name = [self parseName];
if (!name)
return nil;
NSMutableArray *names = [NSMutableArray array];
while (name)
[names addObject:name];
if (![self parseSeparator])
break;
name = [self parseName];
return names;
//
// parseRecord
//
// Attempts to parse a record from the current scan location. The record
// dictionary will use the fieldNames as keys, or FIELD_X for each column
// X-1 if no fieldName exists for a given column.
//
// returns the parsed record as a dictionary, or nil on failure.
//
- (NSDictionary *)parseRecord
//
// Special case: return nil if the line is blank. Without this special case,
// it would parse as a single blank field.
//
if ([self parseLineSeparator] || [scanner isAtEnd])
return nil;
NSString *field = [self parseField];
if (!field)
return nil;
NSInteger fieldNamesCount = [fieldNames count];
NSInteger fieldCount = 0;
NSMutableDictionary *record =
[NSMutableDictionary dictionaryWithCapacity:[fieldNames count]];
while (field)
NSString *fieldName;
if (fieldNamesCount > fieldCount)
fieldName = [fieldNames objectAtIndex:fieldCount];
else
fieldName = [NSString stringWithFormat:@"FIELD_%d", fieldCount + 1];
[fieldNames addObject:fieldName];
fieldNamesCount++;
[record setObject:field forKey:fieldName];
fieldCount++;
if (![self parseSeparator])
break;
field = [self parseField];
return record;
//
// parseName
//
// Attempts to parse a name from the current scan location.
//
// returns the name or nil.
//
- (NSString *)parseName
return [self parseField];
//
// parseField
//
// Attempts to parse a field from the current scan location.
//
// returns the field or nil
//
- (NSString *)parseField
NSString *escapedString = [self parseEscaped];
if (escapedString)
return escapedString;
NSString *nonEscapedString = [self parseNonEscaped];
if (nonEscapedString)
return nonEscapedString;
//
// Special case: if the current location is immediately
// followed by a separator, then the field is a valid, empty string.
//
NSInteger currentLocation = [scanner scanLocation];
if ([self parseSeparator] || [self parseLineSeparator] || [scanner isAtEnd])
[scanner setScanLocation:currentLocation];
return @"";
return nil;
//
// parseEscaped
//
// Attempts to parse an escaped field value from the current scan location.
//
// returns the field value or nil.
//
- (NSString *)parseEscaped
if (![self parseDoubleQuote])
return nil;
NSString *accumulatedData = [NSString string];
while (YES)
NSString *fragment = [self parseTextData];
if (!fragment)
fragment = [self parseSeparator];
if (!fragment)
fragment = [self parseLineSeparator];
if (!fragment)
if ([self parseTwoDoubleQuotes])
fragment = @"\"";
else
break;
accumulatedData = [accumulatedData stringByAppendingString:fragment];
if (![self parseDoubleQuote])
return nil;
return accumulatedData;
//
// parseNonEscaped
//
// Attempts to parse a non-escaped field value from the current scan location.
//
// returns the field value or nil.
//
- (NSString *)parseNonEscaped
return [self parseTextData];
//
// parseTwoDoubleQuotes
//
// Attempts to parse two double quotes from the current scan location.
//
// returns a string containing two double quotes or nil.
//
- (NSString *)parseTwoDoubleQuotes
if ([scanner scanString:@"\"\"" intoString:NULL])
return @"\"\"";
return nil;
//
// parseDoubleQuote
//
// Attempts to parse a double quote from the current scan location.
//
// returns @"\"" or nil.
//
- (NSString *)parseDoubleQuote
if ([scanner scanString:@"\"" intoString:NULL])
return @"\"";
return nil;
//
// parseSeparator
//
// Attempts to parse the separator string from the current scan location.
//
// returns the separator string or nil.
//
- (NSString *)parseSeparator
if ([scanner scanString:separator intoString:NULL])
return separator;
return nil;
//
// parseLineSeparator
//
// Attempts to parse newline characters from the current scan location.
//
// returns a string containing one or more newline characters or nil.
//
- (NSString *)parseLineSeparator
NSString *matchedNewlines = nil;
[scanner
scanCharactersFromSet:[NSCharacterSet newlineCharacterSet]
intoString:&matchedNewlines];
return matchedNewlines;
//
// parseTextData
//
// Attempts to parse text data from the current scan location.
//
// returns a non-zero length string or nil.
//
- (NSString *)parseTextData
NSString *accumulatedData = [NSString string];
while (YES)
NSString *fragment;
if ([scanner scanUpToCharactersFromSet:endTextCharacterSet intoString:&fragment])
accumulatedData = [accumulatedData stringByAppendingString:fragment];
//
// If the separator is just a single character (common case) then
// we know we've reached the end of parseable text
//
if (separatorIsSingleChar)
break;
//
// Otherwise, we need to consider the case where the first character
// of the separator is matched but we don't have the full separator.
//
NSUInteger location = [scanner scanLocation];
NSString *firstCharOfSeparator;
if ([scanner scanString:[separator substringToIndex:1] intoString:&firstCharOfSeparator])
if ([scanner scanString:[separator substringFromIndex:1] intoString:NULL])
[scanner setScanLocation:location];
break;
//
// We have the first char of the separator but not the whole
// separator, so just append the char and continue
//
accumulatedData = [accumulatedData stringByAppendingString:firstCharOfSeparator];
continue;
else
break;
if ([accumulatedData length] > 0)
return accumulatedData;
return nil;
@end
【讨论】：
感谢您的帮助，虽然我可以使用它，但我想了解我遇到的问题，而不是简单地找到解决方案。下面的用户 Ar Ma 似乎发现了问题所在。我还不能投票，因为我是论坛的新手，但以后会回来投票。 乔丹，出于好奇，我从 Matt Gallagher 那里对 CSVParser 产生了兴趣。是否有针对 ARC 更新的版本？ 我在答案中添加了 CSVParser 的 .h 和 .m 以及 ARC【参考方案2】：感谢大家的帮助。我在***上找到了答案，一个2-3岁的论坛（Adding Core Data to existing iPhone project）...
所以问题似乎是，当我第一次创建项目时，我没有要求使用核心数据，只是后来才这样做。根据我上面发布的帖子：
Add the following to supporting files/projectName-Prefix.pch
#import <CoreData/CoreData.h>
一旦我这样做了，persistenceCoordinator 错误就消失了……
哇，在那里学到了很多教训......
【讨论】：
【参考方案3】：-(void)populateDB
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
NSManagedObjectContext *context;
[....]
问题可能是 [self persistentStoreCoordinator]... 你有一个名为“persistentStoreCoordinator”的函数吗？如果没有，你必须编写函数。
[编辑]
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
@synchronized (self)
if (__persistentStoreCoordinator != nil)
return __persistentStoreCoordinator;
NSString *defaultStorePath = [[NSBundle mainBundle] pathForResource:@"myProject" ofType:@"sqlite"];
NSString *storePath = [[[self applicationDocumentsDirectory] path] stringByAppendingPathComponent: @"myProject.sqlite"];
NSError *error;
if (![[NSFileManager defaultManager] fileExistsAtPath:storePath])
if ([[NSFileManager defaultManager] copyItemAtPath:defaultStorePath toPath:storePath error:&error])
NSLog(@"Copied starting data to %@", storePath);
else
NSLog(@"Error copying default DB to %@ (%@)", storePath, error);
NSURL *storeURL = [NSURL fileURLWithPath:storePath];
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
return __persistentStoreCoordinator;
此代码是否在另一个文件中？也许你忘了导入 .h 文件，其中声明了 persistentStoreCoordinator。
【讨论】：
这就是我要找的......出于某种原因，我认为persistenceStoreCoordinator是xcode无法解析的内置属性，所以不，我没有这个方法。但是，当我添加它时，Xcode 我遇到了很多问题，开始时 __persistenceStoreCoordinator 没有被声明。以上是关于在 Core Data 中加载 csv 文件的主要内容，如果未能解决你的问题，请参考以下文章
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