Efficient way to concatenate uncertain strings in Objective-C - objective-c

Question

I want to concatenate some strings from variables if the variables are not nil. If they are nil, I don't want to include them. The following code works but is clunky and grows proportionately more complex with additional variables. Can anyone recommend a more elegant way to do this?
NSString *city = self.address.city== nil ? #"" : self.address.city;
NSString *state = self.address.state== nil ? #"" : self.address.state;
NSString *zip = self.address.zip== nil ? #"" : self.address.zip;
NSString *bestCity;
if (city.length>0&&state.length>0&&zip.length>0) {
bestCity = [NSString stringWithFormat: #"%# %# %#", city, state,zip];
}
else if (city.length>0&&state.length>0) {
bestName = [NSString stringWithFormat: #"%# %#", city,state];
}
else if (city.length>0&&zip.length>0) {
bestCity = [NSString stringWithFormat: #"%# %#", city,zip];
}
else if (city.length>0&&zip.length>0) {
bestCity = [NSString stringWithFormat: #"%# %#", city,zip];
}
else if (city.length>0) {
bestCity = [NSString stringWithFormat: #"%#", city];
}
else if (state.length>0) {
bestCity = [NSString stringWithFormat: #"%#", state];
}
else if (zip.length>0) {
bestCity = [NSString stringWithFormat: #"%#", zip];
}
else {
bestCity = #"";
}

Answer 1

I usually do something like:
NSMutableArray *bestCityArr = [#[] mutableCopy]; // [[NSMutableArray alloc] init];
if (city.length > 0)
[bestCityArr addObject:city];
if (state.length > 0)
[bestCityArr addObject:state];
if (zip.length > 0)
[bestCityArr addObject:zip];
NSString *bestCity = [bestCityArr componentsJoinedByString:#" "];

Answer 2

NSMutableArray *items = [[NSMutableArray alloc] init];
if (self.address.city)
[items appendObject:self.address.city];
if (self.address.state)
[items appendObject:self.address.state];
if (self.address.zip)
[items appendObject:self.address.zip];
NSString *bestCity = [items componentsJoinedByString:#" "];

Answer 3

This code may help you!
- (NSString *)concatenateString
{
NSMutableString *bestCity = [NSMutableString string];
NSString *city = self.address.city ?: #"";
[bestCity appendString:city];
NSString *state = self.address.state ?: #"";
if (state.length > 0) {
[bestCity appendString:#" "];
}
[bestCity appendString:state]];
NSString *zip = self.address.zip ?: #"";
if (zip.length > 0) {
[bestCity appendString:#" "];
}
[bestCity appendString:zip];
return bestCity.length > 0 ? bestCity : #"";
}