Merge an array into a dictionary - ios

Question

I am trying to take an array and merge it into an array of dictionaries but unsure as to how to do it.
I have an array of dictionaries that looks like this:
(
{
caption = a;
urlRep = "12";
},
{
caption = b;
urlRep = "34";
},
{
caption = c;
urlRep = "56";
}
)
and given an array like this:
(12,34,56,78)
I want to merge it into my dictionaries to make it look like this:
(
{
caption = a;
urlRep = "12";
},
{
caption = b;
urlRep = "34";
},
{
caption = c;
urlRep = "56";
},
{
caption = "";
urlRep = "78";
}
)
edit:
I need to also consider removing from the array of dicts if the given array does not contain one of the urlReps.
Any help would be greatly appreciated as I've been stuck trying to figure this out for some time.

Answer 1

Here's a simple, efficient and elegant solution using NSSets to handle unique keys:
NSMutableArray *arrayOfDicts; // your input array of dictionaries
NSArray *urlRepArray; // the new array with string elements
// create a set of potentially new keys (urlReps)
NSMutableSet *urlReps = [NSMutableSet setWithArray:urlRepArray];
// remove existing keys from your original array
[urlReps minusSet:[NSSet setWithArray:[arrayOfDicts valueForKey:#"urlRep"]]];
// merge new dicts to the original array
for (id urlRep in urlReps)
[arrayOfDicts addObject:#{ #"urlRep" : urlRep, #"caption" : #"" }];

Answer 2

Easiest way AFAIK, Filter using valueForKeyPath
//Your array of dictionary I created here for debugging purpose.
NSArray *tmpArray = #[ #{#"caption":#"a",#"urlRep":#"12"},
#{#"caption":#"b",#"urlRep":#"34"},
#{#"caption":#"c",#"urlRep":#"56"}];
//This will give you 12,34,56 in your case
NSArray *existingURLRep = [tmpArray valueForKeyPath:#"urlRep"];
NSMutableArray *targetArray = [[NSMutableArray alloc] initWithObjects:#12, #34,#56, #78, nil]; //Assuming you have your array as you said
[targetArray removeObjectsInArray:existingURLRep];
//remove existing items you will have 78 here now loop through
//this targetArray and add it to your array of dictionary.

Answer 3

(void)filterArray{
NSLog(#"Array before filtering = %#",initialArray);
NSLog(#"given Array = %#",givenArray);
NSMutableSet *urlReps = [NSMutableSet setWithArray:givenArray];
// remove existing records
[urlReps minusSet:[NSSet setWithArray:[initialArray valueForKey:#"urlRep"]]];
// adding new objects
for (id obj in urlReps) {
[initialArray addObject:#{#"caption":#"", #"urlRep" : obj}];
}
// removing objects
NSMutableSet *set = [[NSMutableSet alloc] init];
for (id obj in initialArray) {
NSDictionary *dict = (NSDictionary *)obj;
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"self = %#", dict[#"urlRep"]];
NSArray *filteredArray = [givenArray filteredArrayUsingPredicate:predicate];
if(filteredArray.count == 0) {
[set addObject:dict];
}
}
[initialArray removeObjectsInArray:[set allObjects]];
NSLog(#"Array after filtering = %#",initialArray);
}

Answer 4

NSMutableArray *yourArray;//This will be your original array of dictionary.
NSArray *newArray;//This is your new array which you want to add.
for(id obj in newArray) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"urlRep = %#", id];
NSArray *filteredArray = [locationsArray filteredArrayUsingPredicate:predicate];
if(filteredArray.count == 0) {
[yourArray addObject:#{#"caption":#"", #"urlRep" : id}];
}
}

Answer 5

/*
NSArray *inputArray;//(12,34,56,78)- I assumes you are having array which contains strings. If you are having number then modify the code as you needed
NSMutableArray *colloectionArray;// your total collection
NSMutableArray *tobeMerged;
*/
// Extract the dictionary set only to be merged
for (NSString* aNumber in inputArray) {
for (NSDictionary *aItem in colloectionArray) {
NSString *urlRep= [aItem valueForKey:#"urlRep"];
if (![urlRep isEqualToString:aNumber]) {
[tobeMerged addObject:urlRep];
}
}
}
// Add missed items in collection
for (NSString *aNumber in tobeMerged) {
NSMutableDictionary *newset = [[NSMutableDictionary alloc]init];
[newset setObject:#"" forKey:#"caption"];
[newset setObject:aNumber forKey:#"urlRep"];
[colloectionArray addObject:newset];
}