I need help with indexes and bounds.
I have an NSArray which contains a parsed file separated by « ; ».
So basically :
- (NSArray *) getArrayFromFile{
NSArray *fileArray;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fileName = [NSString stringWithFormat:#"%#/list.txt", documentsDirectory];
NSString *writedStr = [[NSString alloc]initWithContentsOfFile:fileName encoding:NSUTF8StringEncoding error:nil];
fileArray = [writedStr componentsSeparatedByString:#";"];
return fileArray;
}
I want to work with this array.
NSArray* myArray = [self getArrayFromFile];
for(k = 0; j < [myArray count]; k++){
NSLog(#"%#",[myArray objectAtIndex:k]);
}
But when I run trough the returned NSArray, I always have a "terminating with uncaught exception of type NSException"
Here is the full error : http://pastebin.com/qApXU2s0 when the NSArray contains #"Hello",#"World",#"Array Content", and the original file "Hello;World;Array Content;"
Can someone help me with this ..?
Thank you!
If we take a look at your for loop:
for(k = 0; j < [myArray count]; k++){
You can see that you're using a variable k in the first and third parts of the for statement, and a j in the middle part. So whatever j is, it's value is outside the bounds of your array. You'll want to change that j to a k. You could also change your for loop to do fast iteration, in which case you eliminate the k variable and you don't have the possibility of confusion like this.
What #Gavin said was 100% correct.. but a little tip for the future..
for (NSString *stringInArray in myArray)
{
NSLog(#"%#", stringInArray);
}
The above code snippet is a little nicer to work with.
Or, if you are feeling really brave, checkout enumerateObjectsUsingBlock:
Related
I want to be able to view images from a web folder inside my iPhone app. I know how to view the images with a specific url (i.e. www.mywebsite.com/image.jpg). That's easy. I just don't know how to asynchronously load an array. Basically I need to view images with a specific sequence (i.e. mywebsite.com/image_001.jpg, image_002.jpg, image_003.jpg, etc). There may be 10 or 100 images in a folder with that sequence. How do I let my app load images with a sequence?
Following code will sort images of this file format "imageName_number.jpg"
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *webDir=[documentsDirectory stringByAppendingPathComponent:#"WebFolder"];
NSFileManager *filemgr;
NSMutableArray *fileNum;
fileNum=[[NSMutableArray alloc]init];
filemgr = [NSFileManager defaultManager];
//This will give all files of your web directory you can uncomment to get dynamically
//NSArray *filelist = [filemgr contentsOfDirectoryAtPath: webDir error: nil];
// this is just example shows how unsorted will be used to sort image no you can comment this line
NSArray *filelist=[[NSArray alloc]initWithObjects:#"abc_001.jpg",#"def_005.jpg",#"abc_002.jpg",#"abc_0103.jpg",#"abc_0010.jpg",#"abc_008.jpg", nil];
int count = (int)[filelist count];
NSMutableDictionary *dictFileNumWithPath=[[NSMutableDictionary alloc]init];
NSString *imageSeprator=#"_";
for (int i = 0; i < count; i++){
NSString *imageName=[filelist objectAtIndex: i];
if (!([imageName rangeOfString:imageSeprator].location == NSNotFound)) {
NSRange startRange = [imageName rangeOfString:imageSeprator];
NSRange endRange = [imageName rangeOfString:#".jpg"];
NSRange searchRange = NSMakeRange( startRange.location+1, endRange.location-endRange.length);
NSString *strNum= [imageName substringWithRange:searchRange];
NSString *webPath=[webDir stringByAppendingPathComponent:imageName];
[dictFileNumWithPath setObject:[NSNumber numberWithInt:[strNum intValue]] forKey:webPath];
}
}
NSArray *sortedKeysFilePathArray =
[dictFileNumWithPath keysSortedByValueUsingSelector:#selector(compare:)];
NSLog(#"%#", sortedKeysFilePathArray);
I am trying to write the array data into excel (actually it is a CSV, but it is opened in excel). I used the following code to do that:
NSMutableArray *list;
list = [[NSMutableArray alloc] init];
NSString *string = [list componentsJoinedByString:#","];
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:#"yourFileName.csv"];
[data writeToFile:appFile atomically:YES];
It works fine, but the problem is I have 20 objects in my 'list' array and all those 20 objects are written in side by side cells. What I want is to write the first 4 objects in one line and then move to the new line and again write the next 4 objects in that line till all the objects in the list array are completed.
Can anyone help me with this issue?
NSMutableArray *list = ...
NSMutableString *buffer = [NSMutableString string];
for (NSUInteger i = 0; i < list.count; i++) {
NSString *value = list[i];
if (i > 0) {
if (i % 4 == 0) { //after every 4th value
buffer.append("\n"); //end line
}
else {
buffer.append(",");
}
}
buffer.append(value);
//if your values contain spaces, you should add quotes around values...
//buffer.appendFormat(#"\"%#\"", value);
}
NSData *data = [buffer dataUsingEncoding:NSUTF8StringEncoding];
...
To break lines in CSV just input a \r\n in the "end of the line". Be caerfull because in the mac you only need \r or \n (not really sure right now)
during a loop process, my App crash without error. The array count is equal to 175260. With profiler I don't have leaks, so I don't know why the App exit, maybe the CPU usage 100% during a lot of time?
Thank you for your help.
Just this code following crash the App :
for(unsigned int i = 0; i <14;i++)
{
if(findSensor[i]==YES)
{
for(unsigned int j = 1; j <[array count];j++)
{
#autoreleasepool {
if([[[[array objectAtIndex:j] componentsSeparatedByString:#";"] objectAtIndex:0] isEqualToString:[NSString stringWithFormat:#"%d",10*(i+1)]])
{
//Code here
}
}
}
}
}
The full code is :
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fileName = [NSString stringWithFormat:#"%#/%#",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase];
NSFileHandle *fh = [NSFileHandle fileHandleForReadingAtPath:fileName];
NSFileHandle *output = [NSFileHandle fileHandleForReadingAtPath:[NSString stringWithFormat:#"%#/%#10",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase]];
if(output == nil)
{
NSManagedObjectContext *context = [self managedObjectContext];
_recordlocal = [NSEntityDescription insertNewObjectForEntityForName:#"RECORD" inManagedObjectContext:context];
_recordlocal.date = [ibNavSettings interfaceSettings].selectedFileToDataBase;
NSData *inputData = [NSData dataWithData:[fh readDataToEndOfFile]];
NSString *inputString = [[NSString alloc] initWithData:inputData encoding:NSUTF8StringEncoding];
NSArray *array = [[NSArray alloc] initWithArray:[inputString componentsSeparatedByString:#"\n"]];
for(unsigned int i = 0; i <14;i++)
{
if(findSensor[i]==YES)
{
[[NSFileManager defaultManager] createFileAtPath:[NSString stringWithFormat:#"%#/%#%d",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase,10*(i+1)] contents:nil attributes:nil];
NSMutableString *saveString = [[NSMutableString alloc] init];
int count = 0;
for(unsigned int j = 1; j <[array count];j++)
{
#autoreleasepool {
if([[[[array objectAtIndex:j] componentsSeparatedByString:#";"] objectAtIndex:0] isEqualToString:[NSString stringWithFormat:#"%d",10*(i+1)]])
{
[saveString appendString:[array objectAtIndex:j]];
[saveString appendString:#"\n"];
if(i == 0)
count++;
progress++;
pourcent = progress/total;
load = pourcent*100;
if(load%5==0)
[self performSelectorInBackground:#selector(changeUI:)withObject:[NSNumber numberWithFloat:(pourcent)]];
}
}
}
[saveString writeToFile:[NSString stringWithFormat:#"%#/%#%d",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase,10*(i+1)] atomically:YES encoding:NSUTF8StringEncoding error:nil];
if(i == 0)
_recordlocal.count = [[NSNumber alloc] initWithInt:(count/50)];
}
}
_recordlocal.load = [[NSNumber alloc] initWithBool:YES];
NSError *error = nil;
if (![context save:&error]) {
NSLog(#"Core data error %#, %#", error, [error userInfo]);
abort();
}
I would guess that your app is crashing without a readable exception because it is running out of available RAM, especially since you indicated that it is running through a large number of iterations.
For a test, I would recommend doing what Rikkles suggests with the autorelease pool. In addition, since the value of i (and as a result the comparison string) rarely changes, I would create that string outside the j loop as well. This would avoid the creation of a lot of extra strings laying around.
Beyond that, since it appears that you are looking for a string at the beginning of a string that is delimited by a semicolon, I would recommend instead of doing componentsSeparatedByString and then examining element zero that you use the NSString method hasPrefix to check for the condition you are looking for.
Here is an example:
for(unsigned int i = 0; i <14;i++)
{
NSString *searchString = [NSString stringWithFormat:#"%d;", 10*(i+1)];
if(findSensor[i]==YES)
{
for(unsigned int j = 1; j <[array count];j++)
{
if([[array objectAtIndex:j] hasPrefix:searchString])
{
//Code here
}
}
}
}
(I hope this compiles and runs, if it doesn't it should require more than minor tweaks. I am away from my Mac right now.)
If this doesn't help, then something going on inside //Code here must be the culprit.
Why are you creating [array count] autoreleasepools? What's the point of creating so many of them? It could crash because of that. Put the #autoreleasepool outside the for loop.
The only reason I could think that you would do that is if you create so many transient objects inside each iteration of the for loop that you'd want to get rid of them as soon as you got out of the iteration. But there are other ways to do that, including reusing those objects within each iteration.
First suggestion
Just use fast enumeration for the inner loop, you aren't actually using the index 'j' for anything
https://developer.apple.com/library/mac/documentation/General/Conceptual/DevPedia-CocoaCore/Enumeration.html
Second suggestion
Put some NSLog's in place, it will slow everything down, but you need to figure out what point you are failing at. That will help point everyone in the right direction.
Third suggestion
Actually use NSError objects and output their value if an error is thrown:
NSError *writeError = nil;
[saveString writeToFile:[NSString stringWithFormat:#"%#/%#%d",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase,10*(i+1)]
atomically:YES
encoding:NSUTF8StringEncoding
error:&writeError];
if(error != nil) NSLog(#"error writing file: %#", [[writeError userInfo]description]);
Fourth suggestion
You appear to try to be updating the UI from a background thread. This will not work or will cause a crash. UI code can only be called from a main thread. So dont do this:
[self performSelectorInBackground:#selector(changeUI:)withObject:[NSNumber numberWithFloat:(pourcent)]];
If you are already on a background thread this will probably crash because you are creating threads on threads on threads. You instead would want to call:
[self performSelectorOnMainThread:#selector(changeUI:)withObject:[NSNumber numberWithFloat:(pourcent)]];
Fifth suggestion
You may be going over the maximum length for NSString (it's big but I did it once on accident before). You should probably just be appending the file on each iteration of the loop instead, so you don't have an ever growing NSMutableString:
NSString *path = [NSString stringWithFormat:#"%#/%#%d",documentsDirectory,[ibNavSettings interfaceSettings].selectedFileToDataBase,10*(i+1)]
NSFileHandle *fh = [NSFileHandle fileHandleForWritingAtPath:filePath];
NSData *newLine = [#"\n" dataUsingEncoding:NSUTF8StringEncoding];
for(NSString *rowString in array)
{
if([[[rowString componentsSeparatedByString:#";"] objectAtIndex:0] isEqualToString:[NSString stringWithFormat:#"%d",10*(i+1)]])
{
NSData *stringData = [rowString dataUsingEncoding:NSUTF8StringEncoding];
[fh truncateFileAtOffset:[fh seekToEndOfFile]];
[fh writeData:stringData];
[fh truncateFileAtOffset:[fh seekToEndOfFile]];
[fh writeData:newLine];
if(i == 0)
count++;
progress++;
pourcent = progress/total;
load = pourcent*100;
if(load%5==0)
[self performSelectorOnMainThread:#selector(changeUI:)withObject:[NSNumber numberWithFloat:(pourcent)]];
}
}
}
And this has the added benefit of helping you ditch the autoreleasepools
This was invalid
If your array does in fact have 175260 rows, that is probably your issue. You are looping using unsigned int as your index var. Unsigned ints in c only have a max value of 65535. Use an unsigned long int, max 4294967295.
I have read a few posts and found a method. I adapted it to my app, however at [self saveContext]; I get a bad instruction error.
Please let me know why, and if this method makes sense. Also I am using \r because in the csv each item is in its own row.
Thank you in advance
-(void)addData{
NSString *paths = [[NSBundle mainBundle] resourcePath];
NSString *bundlePath = [paths stringByAppendingPathComponent:#"coredatainfo.csv"];
NSString *dataFile = [[NSString alloc] initWithContentsOfFile:bundlePath];
NSArray *dataRows = [dataFile componentsSeparatedByString:#"\r"];
[dataFile release];
FirstCDitem *myItem;
for (int i = 0 ; i < [dataRows count] ; i++)
{
NSArray *dataElements = [[dataRows objectAtIndex:i] componentsSeparatedByString:#","];
NSLog(#"Added: %d %#",i,dataElements);
myItem = (FirstCDitem *)[NSEntityDescription insertNewObjectForEntityForName:#"FirstCDitem" inManagedObjectContext:[self managedObjectContext]];
[FirstCDitem setTitle:[dataElements objectAtIndex:i]];
[self saveContext];
}
}
There are two problems in this code line:
[FirstCDitem setTitle:[dataElements objectAtIndex:i]];
i is the current row number, so it probably makes no sense to use it as index to the dataElements array. Perhaps you want the first element in the row?
setTitle must sent to the instance myItem, not to the class FirstCDItem.
So the line should look like this:
[myItem setTitle:[dataElements objectAtIndex:0]];
I have a NSArray in this way
myArray[0] = [string1, string2, string3, string4, mySecondArray, string5]; (at 0 position)
I write this array inside a txt file in this way
NSString *outputString = #"";
for (int i = 0; i< myArray.count; i++){
outputString = [outputString stringByAppendingString:[[[myArray objectAtIndex:i ] componentsJoinedByString:#"#"] stringByAppendingString:#";"]];
}
NSLog(#"string to write = %#", outputString);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:#"Text.txt"];
NSError *error;
[outputString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
then the result of NSLog is = (position 0 of myArray) (mySecond array is empty)
one#two#three#four#(
)#five;
I want to know:
Why the array wrap?
When I'll go to read this string how can I know that it's mySecondArray?
When you message componentsJoinedByString: on an NSArray object, it calls description on each of its objects and concatenates them in order. For NSString objects, they are the strings themselves. The array wraps because of the way the description method has been implemented.
As for identifying the array while you are reading the string back, I don't think it is possible. You should consider writing the array to the file rather i.e.
[[myArray objectAtIndex:0] writeToFile:filePath atomically:YES];
or
[myArray writeToFile:filePath atomically:YES];
depending on the requirement. This way you will be able to read the elements back properly.