I am having problems in comparing two string objects in objective-c. Here is my situation:
I have two NSString objects in my view controller as follow shown in my code below, in my .h file:
#property(nonatomic,retain) NSString *detailFacility;
in my .m file in viewDidLoad function:
- (void)viewDidLoad
{
NSData *facilityZoneURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:#"some URL..."]]];
NSError *error;
NSDictionary *facilityZoneDict = [NSJSONSerialization JSONObjectWithData:facilityZoneURL options:kNilOptions error:&error];
NSArray *facilityZoneData = [facilityZoneDict objectForKey:#"Data"];
if (![facilityZoneData isKindOfClass:[NSArray class]]) {
//JSON does not returned the Dictionary;
}
facilityZoneArray = [[NSMutableArray alloc] init];
NSLog(#"%#",detailFacility);
for (NSDictionary *item in facilityZoneData) {
NSString *zoneFacilityID = [NSString stringWithFormat:#"%#",[item objectForKey:#"FacilityId"]];
NSLog(#"Facility ID: %# --- Zone ID: %#",detailFacility,zoneFacilityID);
NSLog(#"%#",[zoneFacilityID isEqualToString:detailFacility]? #"YES" : #"NO");
if ([zoneFacilityID isEqualToString:detailFacility]) {
NSLog(#"object added");
}
}
But the problem is it is not comparing the strings as it is surely matches as some position.
here is my NSLOG situation:
2012-04-02 12:12:42.998 CarbonIndex[11078:207] Facility ID: 1056 --- Zone ID: 1056
2012-04-02 12:12:42.999 CarbonIndex[11078:207] NO
As you can see that both the string are accurately matched, but the if-condition does not execute, Tell me what I am missing in it.
It's likely an encoding issue. Try using something like this and see if it helps:
NSLog(#"%#",[zoneFacilityID compare:detailFacility]==NSOrderedSame? #"YES" : #"NO");
Compare works better with different encoding normalizations. See details here: http://weblog.bignerdranch.com/?p=334
More likely than not, one of your strings is not a string. It is an NSNumber and, thus, trying to do a string comparison is failing.
Try changing your logging to verify this:
NSLog(#"Facility ID: %# --- Zone ID: %#",[detailFacility class],
[zoneFacilityID class]);
If that is the case, then you'll likely want to change whatever code that is currently expected to store an NSString to storing an NSNumber, then use isEqual: on the number instances (as that will be faster and more straightforward than number->string conversions everywhere).
Related
Why NSDictionary cannot be written?? I have checked the content of the dictionary: all the instances are of NSString and NSNumber. I checked permissions: a text file with the same name at the same path is written well. Of course, my dictionary is not empty.
NSString *file = ...
NSDictionary *dict = ...
// check dictionary keys
BOOL wrong = NO;
for (id num in [dict allKeys]) {
if (![num isKindOfClass:[NSNumber class]]) {
wrong = YES;
break;
}
}
if (wrong) {
NSLog(#"First");
}
// check dictionary values
wrong = NO;
for (id num in [dict allValues]) {
if (![num isKindOfClass:[NSString class]]) {
wrong = YES;
break;
}
}
if (wrong) {
NSLog(#"Second");
}
if (![dict writeToFile:file atomically:YES]) {
// 0k, let's try to create a text file
NSLog(#"Names writing error!");
[#"Something here... .. ." writeToFile:file atomically:YES encoding:NSUTF8StringEncoding error:nil];
}
Output: "Names writing error!"
Text file is created successfully.
Writing out a dictionary creates a property list, and according to the documentation all keys in a property list must be strings.
... and although NSDictionary and CFDictionary objects allow their keys to
be objects of any type, if the keys are not string objects, the
collections are not property-list objects.
NSNumber objects as keys are not supported.
As #vadian points out, you cannot write plist with numeric keys. But you can use NSKeyedArchiver:
NSURL *documents = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:false error:nil];
NSURL *fileURL = [documents URLByAppendingPathComponent:#"test.plist"];
// this will not work
NSDictionary *dictionary = #{#1: #"foo", #2: #"bar"};
BOOL success = [dictionary writeToFile:fileURL.path atomically:true];
NSLog(#"plist %#", success ? #"success" : #"failure");
// this will
fileURL = [documents URLByAppendingPathComponent:#"test.bplist"];
success = [NSKeyedArchiver archiveRootObject:dictionary toFile:fileURL.path];
NSLog(#"archive %#", success ? #"success" : #"failure");
And you can read it back with NSKeyedUnarchiver:
// to read it back
NSDictionary *dictionary2 = [NSKeyedUnarchiver unarchiveObjectWithFile:fileURL.path];
NSLog(#"dictionary2 = %#", dictionary2);
Note, you can do this with any class that conforms (and properly implements) NSCoding. Fortunately, NSDictionary conforms already. You have to make sure that any objects inside the dictionary, also conform (both NSString and NSNumber do). If you had a custom object in your dictionary, you'd have to make it properly conform yourself.
This is all described in the Archives and Serializations Programming Guide.
I'm trying to take out the "lasttradeprice" in https://www.allcrypt.com/api.php?method=singlemarketdata&marketid=672 but I can't seem to figure out how to grab the "lasttradeprice" piece.
How would I 'filter' the "price" out? None of the other information is relevant.
Current Code:
NSURL * url=[NSURL URLWithString:#"https://www.allcrypt.com/api.php?method=singlemarketdata&marketid=672"]; // pass your URL Here.
NSData * data=[NSData dataWithContentsOfURL:url];
NSError * error;
NSMutableDictionary * json = [NSJSONSerialization JSONObjectWithData:data options: NSJSONReadingMutableContainers error: &error];
NSLog(#"%#",json);
NSMutableArray * referanceArray=[[NSMutableArray alloc]init];
NSMutableArray * periodArray=[[NSMutableArray alloc]init];
NSArray * responseArr = json[#"lasttradeprice"];
for(NSDictionary * dict in responseArr)
{
[referanceArray addObject:[dict valueForKey:#"lasttradeprice"]];
[periodArray addObject:[dict valueForKey:#"lasttradeprice"]];
}
NSLog(#"%#",referanceArray);
NSLog(#"%#",periodArray);
NOTE: Keep in mind I've never worked with JSON before so please keep your answers dumbed down a tad.
Key value coding provides an easy way to dig through that data. Use the key path for the values you want. For example, it looks like you could get the array of recent trades using the path "return.markets.OMC.recenttrades" like this (assuming your code to get the json dictionary):
NSArray *trades = [json valueForKeyPath:#"return.markets.OMC.recenttrades"];
That's a lot more concise than having to dig down one level at a time.
The value returned for a given key by an array is the array of values returned by the array's members for that key. In other words, you can do this:
NSArray *recentprices = [trades valueForKey:#"price"];
And since that's just the next step in the key path, you can combine the two operations above into one:
NSArray *recentprices = [json valueforKeyPath:#"return.markets.OMC.recenttrades.price"];
The only down side here is that there's no real error checking -- either the data matches your expectations and you get back your array of prices, or it doesn't match at some level and you get nil. That's fine in some cases, not so much in others.
Putting that together with the relevant part of your code, we get:
NSURL *url = [NSURL URLWithString:#"https://www.allcrypt.com/api.php?method=singlemarketdata&marketid=672"];
NSData *data = [NSData dataWithContentsOfURL:url];
NSError *error = nil;
NSMutableDictionary *json = [NSJSONSerialization JSONObjectWithData:data options: NSJSONReadingMutableContainers error:&error];
NSArray *recentprices = [json valueforKeyPath:#"return.markets.OMC.recenttrades.price"];
Update: I just noticed that you want the "lasttradeprice", not the array of prices. Given that, the key path to use is simply #"return.markets.OMC.lasttradeprice", and the value you'll get back will be a string. So replace the last line above with:
NSString *lastTradePrice = [json valueforKeyPath:#"return.markets.OMC.lasttradeprice"];
The value you want is buried a few dictionaries deep. One general idea might be to dig recursively, something like this:
- (BOOL)isCollection:(id)object {
return [object isKindOfClass:[NSArray self]] || [object isKindOfClass:[NSDictionary self]];
}
- (void)valuesForDeepKey:(id)key in:(id)collection results:(NSMutableArray *)results {
if ([collection isKindOfClass:[NSDictionary self]]) {
NSDictionary *dictionary = (NSDictionary *)collection;
if (dictionary[key]) [results addObject:dictionary[key]];
for (id deeperKey in [dictionary allKeys]) {
if ([self isCollection:dictionary[deeperKey]]) {
[self valuesForDeepKey:key in:dictionary[deeperKey] results:results];
}
}
} else if ([collection isKindOfClass:[NSArray self]]) {
NSArray *array = (NSArray *)collection;
for (id object in array) {
if ([self isCollection:object]) {
[self valuesForDeepKey:key in:object results:results];
}
}
}
}
Then call it like this:
NSMutableArray *a = [NSMutableArray array];
[self valuesForDeepKey:#"lasttradeprice" in:json results:a];
NSLog(#"%#", a);
I'm evaluating RestKit to use in my project. I've created a simple app that loads some JSON and maps it into Objective-C objects. I'm having a problem correctly mapping a JSON object that has numeric and logical fields. E.g.
{
"integerValue":"5",
"booleanValue":"YES",
}
I want these to map to the following properties in my data object:
#property int integerValue;
#property BOOL booleanValue;
It didn't work out of the box, so I've created a value transformer for that:
[_activityMapping setValueTransformer:[RKBlockValueTransformer valueTransformerWithValidationBlock:^BOOL(__unsafe_unretained Class inputValueClass, __unsafe_unretained Class outputValueClass) {
if([inputValueClass isSubclassOfClass:[NSString class]] && [outputValueClass isSubclassOfClass:[NSNumber class]]) {
return YES;
}
else {
return NO;
}
} transformationBlock:^BOOL(id inputValue, __autoreleasing id *outputValue, __unsafe_unretained Class outputClass, NSError *__autoreleasing *error) {
if([[inputValue class] isSubclassOfClass:[NSString class]] && [outputClass isSubclassOfClass:[NSNumber class]]) {
NSString *inputString = (NSString *)inputValue;
if([inputString isEqualToString:#"YES"] || [inputString isEqualToString:#"NO"]) {
*outputValue = [NSNumber numberWithBool:[inputString boolValue]];
}
else {
*outputValue = [NSNumber numberWithInt:[inputString intValue]];
}
}
else {
*outputValue = [inputValue copy];
}
return YES;
}]];
This code works, but looks ugly. Note how I have to check the input value to see if it's a boolean or an integer. Any suggestions on an elegant solution to this problem?
Please note that I'm using RestKit. I do know about NSJSONSerialization and know how to parse JSON in code. If you suggest a non-RestKit solution, please explain why do you not recommend using RestKit.
The issue is not occurring at the RestKit level but at the JSON level itself.
According to the JSON spec Boolean values should be represented with true/false not YES/NO. If you update your JSON to be semantically correct then RestKit should do the right thing.
Ok. So according to my understanding of your answer, your main problem lies in mapping the data in the JSON object to their very own designated variables.
So, I'd recommend using the conventional NSJSONSerialization approach.
So, first up. You need to store your JSON object in an NSData object. Now, you're most likely downloading the data from a simple URL. So, this is what you'd do :
//This part is just to download the data. If you're using another method - that's fine. Just make sure that the download is in NSData format
NSURL *url = [[NSURL alloc] initWithString : #"YOUR_URL_HERE"];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL : url];
NSData *jsonData = [NSURLConnection sendSynchronousRequest:request
returningResponse:nil
error:nil];
Now, you need to map those to the NSDictionary... Here's how :
//This is the actual NSJSONSerialization part.
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData
options:NSJSONReadingMutableLeaves
error:nil];
Now, just map the values to your designated properties.
_integerValue = (int)[jsonDict objectForKey:#"integerValue"];
_booleanValue = (BOOL)[jsonDict objectForKey:#"booleanValue"];
I came to notice that executing a for/in operation in objective c on an initialized empty NSMutableArray was not working as expected.
Simplified code is :
+(void) convertArray: (NSMutableArray*)arrayIN {
NSMutableArray *arrayOUT = [NSMutableArray array];
NSLog(#"is nil %d - count %d", !arrayIN, [arrayIN count]);
for(NSObject *o in arrayIN)
[arrayOUT addObject:[o convertToAnotherClass]];
}
Actual code is :
+(BOOL) writeTasks: (NSArray*)tasksArray {
NSMutableArray *arr = [NSMutableArray array];
NSLog(#"is nil %d - count %d", !arr, [arr count]);
for(Task *t in tasksArray)
[arr addObject:[t getDictionary]];
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:arr options:NSJSONWritingPrettyPrinted error:&error];
if (! jsonData) {
NSLog(#"Got an error: %#", error);
return NO;
} else {
//NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
[jsonData writeToFile:path options:NSDataWritingAtomic error:nil];
return YES;
}
}
the suprising thing is that executing [dummyClass convertArray:[NSMutableArray array]] is showing this :
2012-06-25 13:51:34.236 Planorama[740:707] is nil 0 - count 0
2012-06-25 13:51:34.239 Planorama[740:707] -[__NSArrayM convertToAnotherClass]: unrecognized selector sent to instance 0xde9b580
(lldb)
Why ? arrayIN is empty, why is convertToAnotherClass even called ?
if you use the block based enumeration it will work the way you want.
Also, the output indicates that o is set to some instance of something, so you may have another problem.
Elegant way to get all objects of a specific type in an Objective-C array
Lastly, it looks like this is a static method, but your example calls it as an instance method.
As Joshua Smith pointed out : I am not checking the count of the iterated array. The iterated array was not empty and contained itself because if a mistyped line :
[tasks addObject:tasks]
instead of
[tasks addObject:task]
in a previous method..
Thanks everyone !
PS : the link of Joshua Smith is very useful ! Future readers : check it out !
Is there any way to get NSLog to print out an entire JSON file. I am currently saying
NSString *deviceInfo = [NSString stringWithFormat:#"%# %#",
[[UIDevice currentDevice]model], [[UIDevice currentDevice]systemVersion]];
NSDictionary *json = [deviceInfo JSONValue];
NSLog(#"json file = %#", json);
And it is printing out "json file = (null)"
Thanks
Clinton
I think you’re misunderstanding what JSON is for. The string you’re passing to -JSONValue isn’t a valid JSON string, so it’s returning nil. You might as well just construct the dictionary yourself:
UIDevice *device = [UIDevice currentDevice];
NSDictionary *deviceInfo = [NSDictionary dictionaryWithObjectsAndKeys:[device model], #"deviceModel", [device systemVersion], #"deviceSystemVersion", nil];
Then if you want the JSON string representation of the object (for sending to your server, for instance):
NSString *jsonDeviceInfo = [deviceInfo JSONRepresentation];
Are you sure that your code works correctly? Your NSDictionary seems to be nil ...
Could you please post the implementation of JSONValue?
If an object doesn't print as expected you can always override the -(NSString *) description method through an extension and it will print how you've specified :)