NSDictionary Filtering and Sorting
I am working on a App that makes use of a JSON API and I am Using the JSON for Objective C Framework to get the Data into a NSDictionary
. The dictionary loos like this:
({
admitted = "<null>";
agreed = "<null>";
"area_id" = 1;
"area_name" = "Digitales, Urheber-/Patentrecht, Datenschutz";
created = "2010-08-17 12:41:03";
"current_draft_content" = Bla Bla Bla";
"current_draft_created" = "2010-08-17 12:42:44";
"current_draft_formatting_engine" = compat;
"discussion_url" = "http://piratenpad.de/OpenSourceZwang";
id = 502;
"informed_supporter_count" = 11;
"issue_accepted" = "";
"issue_admission_time" = "8 days";
"issue_closed" = "";
"issue_created" = "2010-08-17 12:41:03";
"issue_discussion_time" = "15 days";
"issue_fully_frozen" = "";
"issue_half_frozen" = "";
"issue_id" = 242;
"issue_population" = 372;
"issue_ranks_available" = 0;
"issue_state" = new;
"issue_verification_time" = "8 days";
"issue_vote_later" = 0;
"issue_vote_now" = 0;
"issue_voter_count" = "<null>";
"issue_voting_time" = "8 days";
name = "Alte 开发者_运维百科& unsupportete Software, muss Open Source werden";
"negative_votes" = "<null>";
"policy_initiative_quorum_den" = 100;
"policy_initiative_quorum_num" = 10;
"policy_issue_quorum_den" = 100;
"policy_issue_quorum_num" = 10;
"policy_majority_den" = 2;
"policy_majority_num" = 1;
"policy_majority_strict" = 1;
"positive_votes" = "<null>";
rank = "<null>";
revoked = "<null>";
"satisfied_informed_supporter_count" = 7;
"satisfied_supporter_count" = 7;
"suggested_initiative_id" = "<null>";
"supporter_count" = 11;
},
{
admitted = "<null>";
agreed = "<null>";
"area_id" = 1;
"area_name" = "Digitales, Urheber-/Patentrecht, Datenschutz";
created = "2010-08-17 14:09:14";
"current_draft_content" = "Bla Bla Bla";
"current_draft_created" = "2010-08-17 14:09:31";
"current_draft_formatting_engine" = compat;
"discussion_url" = "";
id = 508;
"informed_supporter_count" = 0;
"issue_accepted" = "2010-08-14 01:51:45";
"issue_admission_time" = "15 days";
"issue_closed" = "";
"issue_created" = "2010-08-14 01:34:26";
"issue_discussion_time" = "30 days";
"issue_fully_frozen" = "";
"issue_half_frozen" = "";
"issue_id" = 30;
"issue_population" = 603;
"issue_ranks_available" = 0;
"issue_state" = accepted;
"issue_verification_time" = "15 days";
"issue_vote_later" = 9;
"issue_vote_now" = 0;
"issue_voter_count" = "<null>";
"issue_voting_time" = "15 days";
name = "Grundrecht: Alternative Formulierung";
"negative_votes" = "<null>";
"policy_initiative_quorum_den" = 100;
"policy_initiative_quorum_num" = 10;
"policy_issue_quorum_den" = 100;
"policy_issue_quorum_num" = 10;
"policy_majority_den" = 3;
"policy_majority_num" = 2;
"policy_majority_strict" = 0;
"positive_votes" = "<null>";
rank = "<null>";
revoked = {
};
"satisfied_informed_supporter_count" = 0;
"satisfied_supporter_count" = 0;
"suggested_initiative_id" = "<null>";
"supporter_count" = 0;
}
)
What is a good way to get all object where the "issue_id" is 2 oder 6 or what ever to display a grouped UITabeView
with all objects with the same "issue_id" in one group?
You can use NSSortDescriptor to sort:
NSSortDescriptor *dateSortDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"issue_id" ascending:YES selector:@selector(compare:)] autorelease];
[youDictionaryArray sortUsingDescriptors:[NSArray arrayWithObjects:dateSortDescriptor, nil]];
And/or NSPredicate to get some ID only:
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(issue_id == %i)", 2];
NSArray *newArray = [youDictionaryArray filteredArrayUsingPredicate:predicate];
There are several ways. You can use NSPredicate
and use the NSArray method -filteredArrayUsingPredicate:
. Or on iOS 4 you use a filtering block: -indexesOfObjectsPassingTest:
then use -objectsAtIndexes:
to get the objects.
Otherwise the best is you just iterate through the array and filter the items you want into a new one:
// Given a NSArray *items
NSMutableArray *filteredItems = [NSMutableArray array];
for (NSDictionary *item in items) {
if (/* your condition */) {
[filteredItems addObject: item];
}
}
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