ios - Merging two NSArray removing duplicates -

i have array of cities , array of countries. these 2 objects have property in common: city name. need create new array adding countries have city name not there in cities array.

i tried iterating on both arrays, comparing city name , adding different 1 new array. result that, while checks first city, cities have name added array , other cities in cities array there.

self.filteredcountriesarray = [nsmutablearray new];  (country* country in self.countries) {     (city *city in self.cities) {         if (![country.city isequaltostring:city.name]) {             [self.filteredcountriesarray addobject:country];         }     } } 

suggestions?

not sure whether understand want, guess you'd this:

for (country *country in self.countries) {     bool found = no;      (city *city in self.cities) {         if ([country.city isequaltostring:city.name]) {             found = yes;             break;         }     }      if (!found) {         [self.filteredcountriesarray addobject:country];     } } 

to speed up, i'd create nsset city names first:

nsmutableset *citynames = [nsmutableset set]; (city *city in self.cities) {     [citynames addobject:city.name]; }  (country *country in self.countries) {     if (![citynames containsobject:county.city]) {         [self.filteredcountriesarray addobject:country];     } }