I'm trying to do the following - I have an Array in which some strings are stored. These strings shall be used to call an NSArray. An example will clarify what I'm trying to do:
This is the working code that I'm trying to achieve ("briefing0" is of type NSArray):
NSString *path = [docsDir stringByAppendingPathComponent:[briefing0 objectAtIndex:indexPath.row]];
This is the "same" code that I'm trying to use:
int i = 0;
NSString *path = [docsDir stringByAppendingPathComponent:[(NSArray *)[NSString stringWithFormat:#"briefing%d", i] objectAtIndex:indexPath.row]];
Any ideas?
Thanks in advance!
Tom
Assuming that briefing0 is actually a property, then yes, this is possible (and not uncommon) in ObjC via KVC.
int i = 0;
NSString *prop = [NSString stringWithFormat:#"briefing%d", i];
NSArray *array = [self valueForKey:prop];
NSString *value = [array objectAtIndex:indexPath.row];
... etc. ...
-valueForKey: is the piece you're looking for. Note that this will throw an exception if you construct a key that does not exist, and so must be used with extreme care.
Related
I have a code that creates an NSString and separates value with a comma. What I need to do is take that string, convert it to a NSArray and separate each value from the NSString between the commas, then iterate through each one. The code below returns the array as a single string
NSString *emails = #"testemail#gmail.com, testemail2#gmail.com";
NSArray *listItems = [emails componentsSeparatedByString:#", "];
for (int i = 0; i < [listItems count]; i++) {
NSString *address = (NSString*) [listItems objectAtIndex:i];
NSLog (#"ADDRESS: %#", address);
The Log shows the response testemail#gmail.com, testemail2#gmail.com when I want it to separate each one individually. Should this be an NSMutableArray instead?
The code is correct. You'll get two (separate) lines starting with ADDRESS:
But nowadays (actually since 2009!) it's highly recommended to use Fast Enumeration if the loop index is not needed
NSString *emails = #"testemail#gmail.com, testemail2#gmail.com";
NSArray *listItems = [emails componentsSeparatedByString:#", "];
for (NSString *email in listItems) {
NSLog(#"ADDRESS: %#", email);
}
I have getting data from plist to NSString, in result I see something like this "{{1848,594},{154,176}}". What is the best way to convert every single number to separate NSInteger?
NSString *frame = [myPlistKey objectForKey:#"frame"];
How to convert frame to 4 separate integers?
In this specific case, it looks like you are trying to parse the string representation of an NSRect, in which case you can just use NSRectFromString() from the Foundation framework.
Edit:
Since you are not much specific, I will try to cover your situation. If i count with the fact you have NSString *frame filled with {{1848,594},{154,176}}:
NSString *stringWithoutLeftBracket = [frame
stringByReplacingOccurrencesOfString:#"{" withString:#""];
NSString *stringWithoutRightBracket = [stringWithoutLeftBracket
stringByReplacingOccurrencesOfString:#"}" withString:#""];
NSArray *frameArray = [stringWithoutRightBracket componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:#","]];
Then you can access objects with indexes like:
NSInteger integer = [[frameArray objectAtIndex:0] integerValue];
But also you could use a for loop like this:
for (NSInteger integer in frameArray) {
// Do something
}
In my opinion you have a string made from rect, means you could convert it.
I have an NSArray with values that I am pulling from an NSDictionary using a selector to sort with which has the following values:
John
Brian
Alex
....
Dave
When I use the code below, since they are being compared as strings, the list comes back with:
NSArray *array = [[[self myDictionary] allValues] sortedArrayUsingSelector:#selector(compare:)];
John
Dave
Brian
...
How can I get these values to sort correctly where they are in order 1, 2, 3, etc.? I've looked at several different examples for sorting, but have not been able to find an example like mine. I must also mention that I'm new to objective-c and iOS. Any help would be greatly appreciated.
Thanks!
I was actually able to figure out the solution. I created an NSComparisonResult block using custom logic to read the number portion off of the front of each string and then comparing them numerically:
NSComparisonResult (^sortByNumber)(id, id) = ^(id obj1, id obj2)
{
//Convert items to strings
NSString *s1 = (NSString *)obj1;
NSString *s2 = (NSString *)obj2;
//Find the period and grab the number
NSUInteger periodLoc1 = [s1 rangeOfString:#"."].location;
NSString *number1 = [s1 substringWithRange:NSMakeRange(0, periodLoc1)];
NSUInteger periodLoc2 = [s2 rangeOfString:#"."].location;
NSString *number2 = [s2 substringWithRange:NSMakeRange(0, periodLoc2)];
//Compare the numeric values of the numbers
return [number1 compare:number2 options:NSNumericSearch];
};
Then I sort my array by calling:
NSArray *array = [[[self myDictionary] allValues] sortedArrayUsingComparator:sortByNumber];
I have a NSMutableArray that is loaded with a inforamtion from a dictionary...
[self.data removeAllObjects];
NSMutableDictionary *rows = [[NSMutableDictionary alloc] initWithDictionary:[acacheDB.myDataset getRowsForTable:#"sites"]];
self.data = [[NSMutableArray alloc] initWithArray:[rows allValues]];
There are two key value pairs in the rows dictionary.
I need to sort the self.data NSMutableArray in alphabetical order.
How is this accomplished??
thanks
tony
If the values are plain strings you can use the following to create a sorted array:
NSArray *sorted = [values sortedArrayUsingSelector:#selector(caseInsensitiveCompare:)];
This should do:
[self.data removeAllObjects];
NSArray *values = [[acacheDB.myDataset getRowsForTable:#"sites"] allValues];
NSSortDescriptor *alphaDescriptor = [[NSSortDescriptor alloc] initWithKey:#"DCFProgramName" ascending:YES selector:#selector(localizedCaseInsensitiveCompare:)];
NSArray *sortedValues = [values sortedArrayUsingDescriptors:[NSMutableArray arrayWithObjects:alphaDescriptor, nil]];
[alphaDesc release];
[self.data addObjectsFromArray:sortedValues];
There's no need to clear an NSMutableArray if you're replacing it shortly afterwards.
There's no need to create an additional NSMutableDictionary, if you're not modifying anything in it.
There's no need to create an additional NSMutableArray, if you could just as well just add the values to the existing one.
Also: There are some serious memory leaks in your code. (2x alloc + 0x release = 2x leak)
Edit: updated code snippet to reflect OP's update on data structure.
I have an method that reads an xml file and stores the xml nodes at a certain XPath-path in an NSArray called *nodes. What I want to do is take each one of the items in the array and add it to a core data entity called Category with the attribute of "name".
I have tried a number of different ways of creating the entity but I'm not sure about the correct way to do this effectively. This is the code used to create the NSArray, any ideas on how to implement this? (ignore the NSError, I will fix this in the final version)
- (IBAction)readCategories:(id)sender
{
NSString *xmlString = [resultView string];
NSData *xmlData = [xmlString dataUsingEncoding: NSASCIIStringEncoding];
NSXMLDocument *xmlDoc = [[NSXMLDocument alloc] initWithData:xmlData options:nil error:nil];
//XPath
NSError *err=nil;
NSArray *nodes = [xmlDoc nodesForXPath:#"//member[name='description']/value/string" error:&err];
}
EDIT - My loop code
NSArray *nodes = [xmlDoc nodesForXPath:#"//member[name='description']/value/string" error:&err];
int arrayCount = [nodes count];
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSXMLElement *categoryEl;
NSString *new = [catArrayController newObject];
int i;
for (i = 0; i < arrayCount; i++)
{
[categoryEl = [nodes objectAtIndex:i]];
[new setValue:[categoryEl stringValue] forKey:#"name"];
[catArrayController addObject:new];
}
[pool release];
Here's how I'd write it:
for (NSXMLElement *categoryElement in nodes) {
NSManagedObject *newObject = [catArrayController newObject];
[newObject setValue:[categoryElement stringValue] forKey:#"name"];
[catArrayController addObject:newObject];
[newObject release];
}
First, I'm using the Objective-C 2.0 for-each syntax. This is simpler than using index variables. I eliminated i and arrayCount.
Next, I took out your NSAutoreleasePool. None of the objects in the loop are autoreleased, so it had no effect. (The newObject method returns a retained object which is, by convention, what methods with the word new in their name do) This is also why I release newObject after adding it to the array controller. Since I'm not going to be using it any more in this method, I need to release it.
Also, you had defined new (which I renamed newObject) as an NSString. Core Data objects are always either an instance of NSManagedObject or a subclass of NSManagedObject.
Your line [categoryEl = [nodes objectAtIndex:i]] won't compile. That's because the bracket syntax is used to send a message to an object. This is an assignment statement, so the bracket syntax is not needed here. (This line is also not necessary any more because of I've changed the loop to use the for-each syntax) But, for future reference, categoryEl = [nodes objectAtIndex:i]; would have worked.
What part are you having trouble with? There shouldn't be much more to it than looping through the array, creating a new managed object for each entry, and setting the correct attributes. You can create the managed object with NSEntityDescription's -insertNewObjectForEntityForName:inManagedObjectContext: method.