I wrote a method that takes in parameter a SQL requests (SELECT name FROM table) and return a NSDictionnary with first letter of word as key
Dictionnary
{
A = ("Arbre", "Armoise");
B = ("Bob", "Bill") ;
...
}
So I'm stuck with that, Now if my request look like SELECT name_en FROM table WHERE name_fr LIKE "Bob"
My dictionnary will look like :
Dic {
B = ("Bob");
}
And I just want to display Bob. So How can I get this value ? I already tried objectAtIndex and [[dic allKeys] objectAtIndex:0];
But I got nothing
Thanks !
There is no such thing as the "first object" in a dictionary. A dictionary is an unordered collection.
I'm not 100% certain what you're asking but what you could do is take the array of keys...
NSArray *keys = [dictionary allKeys];
and then sort the array
NSArray *sortedKeys = [keys sortedArrayUsing... // choose your own method for sorting
Then get the object related to the first sorted key...
id firstObject = dictionary[[sortedKeys firstObject]];
Related
I have the following categoryNames array.
And now, I have categoryTempElements and it has cName property. I need to know how to order categoryTempElements with a order of categoryNames.
UPDATE: I have added sortOrder property to Category object and tried the following but order does not change.
for (Category* a in categoryTempElements) {
int index = (int)[categoryNames indexOfObject:a.cName];
a.sortOrder = index;
}
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"sortOrder" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray = [categoryTempElements sortedArrayUsingDescriptors:sortDescriptors];
Another way could be without using sortedArrayUsingComparator, using two for-loops. Declare a new Mutable array called sortedCategoryElements and compare the categoryNames in categoryTempElements, If matches add it to a new array sortedCategoryElements:
NSMutableArray *sortedCategoryElements = [NSMutableArray new];
for (NSString *name in categoryNames) {
for (Category *category in categoryTempElements) {
if (name == category.cName) {
[sortedCategoryElements addObject:category];
break;
}
}
}
I tried with your set of data, it worked for me.
Hope it helps!
You need first convert your categoryNames array into dictionary with NSString key and NSNumber int value, the value will be the order in the array
//this is example code, this will be your first array (reference value array)
NSArray * array = #[#"prueba",#"prueba2",#"prueba3"];
//first you need convert this array in NSDictionary
NSMutableDictionary * arrayDict = [NSMutableDictionary dictionary];
int counter = 0;
for (NSString * value in array) {
if(arrayDict[value] == nil)
{
arrayDict[value] = [NSNumber numberWithInt:counter];
}
counter++;
}
After that then you can get the value and order with sortedArrayUsingComparator method, something like this
//this is an example of your second array categoryTempElements
NSArray * arrayOfObjs = #[[testObject testObjectWithName:#"prueba3"],[testObject testObjectWithName:#"prueba"],[testObject testObjectWithName:#"prueba2"]];
NSArray * sorted = [arrayOfObjs sortedArrayUsingComparator:^NSComparisonResult(testObject * _Nonnull obj1, testObject * _Nonnull obj2) {
if([((NSNumber*)arrayDict[obj1.cName]) intValue] < [((NSNumber*)arrayDict[obj2.cName]) intValue]){
return NSOrderedAscending;
}
if([((NSNumber*)arrayDict[obj1.cName]) intValue] > [((NSNumber*)arrayDict[obj2.cName]) intValue]){
return NSOrderedDescending;
}
return NSOrderedSame;
}];
for (testObject * obj in sorted) {
NSLog(#"%#",obj.cName);
}
And voila in sorted you will have your array of object sorted by your first array NSString order
Hope this helps
Create a dictionary with cName as the key and the Category object as the value. Then iterate over the categoryNames array, and build another array by using each item in categoryNames as the key. The resulting array should be sorted in the same order as categoryNames.
NSArray has a method sortedArrayUsingComparator: which sorts an array using the ordering implemented by the block you pass. This block, of type NSComparator, is passed references to two elements of your array and you must return the order of those two elements.
And now, I have categoryTempElements and it has cName property.
So your block will be passed two categoryTempElements, you need to access the cName property of each, and compare the resulting two values...
I need to know how to order categoryTempElements with a order of categoryNames
by the position, i.e. the index, of those values in your categoryNames array. The method indexOfObject: provides that index for you.
So put that together and your problem is solved.
HTH
So I have this NSDictionary like so:
NSDictionary *productionSchedule = [[[NSMutableDictionary alloc]initWithDictionary:[[areaData GetProductionScheduleData:communityDesc] objectForKey:#"Root"]] autorelease];
The data for the NSDictionary is coming from an API and due to the fact that NSDictionary does not do ordering, the order of the data in API is different in the NSDictionary, so now I am trying to put the keys of the NSDictionary into an NSMutableArray to handle the ordering. In my NSDictionary I have a value called SortOrder and I am trying to put the data in NSDictionary into NSMutableArray based on this value SortOrder (I have about 389 items and the SortOrder goes from 0 - 389) How would I do this?
I have this screenshot that will show you what my data is like:
What I am trying to do is put the key 'V3C0183' but as the 82nd item (there will be 81 items before this)
I am assuming I will have to do a foreach loop like so:
NSMutableArray *prodSchedSortedKeys
for(int i = 0;i<[productionSchedule count];i++)
{
[prodSchedSortedKeys addObject: ? ];
}
I just dont know what the next step would be to add an object based off the sort order....please help.
NSDictionary *dic = //your dictionary;
NSArray<NSDictionary *> *values = dic.allValues;
[values sortedArrayUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
return [obj1[#"SortOrder"] integerValue] > [obj2[#"SortOrder"] integerValue];
}];
Now the dic is ordered.
But this is not the best solution of this problem. Server's data should be ordered instead, that the key like "VC31083" should in the key-value pairs too.
Edit1: sortedArrayUsingComparator: is used for normal sort of array, the performance isn't very well if the content is too large. Especially in this compare, it do addition actions: get value from dictionary, transform NSString to int, and then compare. You can Log to see how much time it spend on this sort with your data.
NSMutableDictionary/NSDictionary can't do that. Take a look at e.g. Matt Gallaghers OrderedDictionary.
Also take a look at this answer:
Getting NSDictionary keys sorted by their respective values
I have an NSMutableDictionary of websites
[dictionaryOfSites setObject:#"http://www.example.com" forKey:#"Example.com"];
[dictionaryOfSites setObject:#"http://www.site1.com" forKey:#"Site1"];
[dictionaryOfSites setObject:#"http://www.apple.com" forKey:#"Apple"];
I know you can't sort a dictionary. But I've read that other people have used an NSMutableArray as the key and the array can be sorted.
So if I setup a new array
[[arrayKey alloc] initWithObjects:#"Example.com", #"Site1", #"Apple", nil];
I would then modify my first snippet to
[dictionaryOfSites setObject:#"http://www.example.com" forKey:[arrayForKey objectAtIndex:0]];
[dictionaryOfSites setObject:#"http://www.site1.com" forKey:[arrayForKey objectAtIndex:1]];
[dictionaryOfSites setObject:#"http://www.apple.com" forKey:[arrayForKey objectAtIndex:2]];
In this simple problem, I had 3 sites so I "hard" coded it. How would I do the same thing if my list of sites was 100? How would the order of the sites be maintained?
If I sort my array
[arrayKey sortUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
Wouldn't index 2 become index 0? If it becomes index 0 then you can see the dictionaryOfSites has the wrong label with the URL.
So you can use a custom class (as I mentioned above in my comment), or better yet use an NSDictionary to store the values as MarkM suggested.
EDIT: "i don't have to maintain a dictionary. its a new app from the ground up."
Since you don't need to start with one big dictionary like you posted, it would be better to just store individual dictionary objects for each site in an array and not have to worry about the conversion.
// Setup the initial array
NSMutableArray *arrayOfSites = [NSMutableArray new];
[arrayOfSites addObject:#{#"Name" : #"Example.com",
#"URL" : #"http://www.example.com"}];
[arrayOfSites addObject:#{#"Name" : #"Site1",
#"URL" : #"http://www.site1.com"}];
[arrayOfSites addObject:#{#"Name" : #"Apple",
#"URL" : #"http://www.apple.com"}];
// At this point, arrayOfSites contains a dictionary object for each site.
// Each dictionary contains two keys: Name and URL with the appropriate objects.
// Now we just need to sort the array by the Name key in the dictionaries:
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"Name" ascending:YES];
[arrayOfSites sortUsingDescriptors:[NSArray arrayWithObjects:descriptor, nil]];
NSLog(#"%#", arrayOfSites);
Results:
2013-05-07 18:19:08.386 Testing App[75712:11f03] (
{
Name = Apple;
URL = "http://www.apple.com";
},
{
Name = "Example.com";
URL = "http://www.example.com";
},
{
Name = Site1;
URL = "http://www.site1.com";
} )
To access the data, you would use:
NSString *name = [[arrayOfSites objectAtIndex:indexPath.row] objectForKey:#"Name"];
Note that arrayOfSites should be a declared property of your class so that you can access it from different methods.
What you need to do is store your NSDictionary objects in the array and then access a value from that array to do the sorting if you wish. You don't actually store a new string for the sorting. You just check the value of a certain key in the dictionary at the index in the array.
Here is a good source for sorting an array of dictionaries
I have a problem which I can't solve for a long time. I have a JSON response from the server which is parsed to NSDictionary lastMsgs as in the image below:
So for example 1323 it's a key and it associated with NSDictionary (which contains keys such as body, subject etc and values). So the problem I need in some way delete an entry which nested NSDictionary value has entry : type = 1. I don't know how to do this. I tried to do this:
NSMutableArray* _ModelVals = [[lastMsgs allValues] mutableCopy];
for (int i =0; i<[_ModelVals count]; i++) {
string_compare = [NSString stringWithFormat:#"%#" , [_ModelVals objectAtIndex:i]];
if ([string_compare rangeOfString:#"type = 1"].location != NSNotFound) {
[_ModelVals removeObjectAtIndex:i];
}
}
But it is work not correctly and delete not all entries which has type = 1. So the question - how can I implement this and delete entry in nested NSDictionary?
There is no value "type = 1" in the dictionary. That's just the log. You get the value of a key in a dictionary using [dict objectForKey:#"key"] or dict[#"key"].
Judging from your log, the type seems to be an NSNumber, not an NSString. Just get the int representation of it (assuming the type is an integer) and use a simple C int to int comparison.
And you can't filter an array like that. You will skip an entry. If you remove an entry, you have to decrease i by 1.
Or use this simpler solution:
NSSet *keys = [lastMsgs keysOfEntriesPassingTest:^BOOL(id key, id obj, BOOL *stop) {
return [obj[#"type"] intValue] == 1;
}];
NSMutableDictionary *dict = [lastMsgs mutableCopy];
[dict removeObjectsForKeys:[keys allObjects]];
This will first collect the keys of all objects (dictionaries) that have a type of 1 and then remove those from a mutable copy of the original dictionary.
You cannot add or remove objects from a collection while enumerating though it. I would create a another array that you can store references to the objects that you want to delete and remove them after you have looped though it.
I call an URL that returns me JSON (I use JSONKit). I convert it to a NSString that is this way:
[{"name":"aaaaaa","id":41},{"name":"as","id":23},...
And so on. I want to fill an UIPickerView with only the "name" part of the JSON. But, when the user selects a name, i need the "id" parameter, so i've thought to fill a NSDictionary with the JSON (setValue:id for key:name), so i can get the value picked by the user, and get the id from the dictionary. how could I fill an array with only the "name" of the JSON?
Im a bit lost with the JSONKit library, any guidance? Thank you.
First of all I don't think that its a good idea to have name as key in a dictionary, since you can have many identical names. I would go for id as key.
Now, what you could do is:
NSString *myJson; //Suppose that this is the json you have fetched from the url
id jsonObject = [myJson objectFromJSONString];
// Now you have an array of dictionaries
// each one having 2 key/value pairs (name/id)
NSArray *names = [jsonObject valueForKeyPath:#"name"];
NSArray *ids = [jsonObject valueForKeyPath:#"id"];
// Now you have two parallel arrays with names / ids
Or you could just iterate your json object and handle the data yourself:
for (id obj in jsonObject)
{
NSString *name = [obj valueForKey:#"name"];
NSNumber *id = [obj valueForKey:#"id"];
// Do whatever you like with these
}