CODEWITHSUNDEEP
objective-cnsstringnsmutablestring
cyclingIsBetter
cyclingIsBetter

Reputation: 17591

Objective C: convert a NSMutableString in NSString

I have an NSMutableString, how can I convert it to an NSString?

Upvotes: 70

Views: 52175

Answers (2)

Regexident
Regexident

Reputation: 29552

Either via:

NSString *immutableString = [NSString stringWithString:yourMutableString];

or via:

NSString *immutableString = [[yourMutableString copy] autorelease];
//Note that calling [foo copy] on a mutable object of which there exists an immutable variant
//such as NSMutableString, NSMutableArray, NSMutableDictionary from the Foundation framework
//is expected to return an immutable copy. For a mutable copy call [foo mutableCopy] instead.

Being a subclass of NSString however you can just cast it to an NSString

NSString *immutableString = yourMutableString;

making it appear immutable, even though it in fact stays mutable.
Many methods actually return mutable instances despite being declared to return immutable ones.

Upvotes: 107

Jose Ibanez
Jose Ibanez

Reputation: 3345

NSMutableString is a subclass of NSString, so you could just typecast it: 

NSString *string = (NSString *)mutableString;

In this case, string would be an alias of mutalbeString, but the compiler would complain if you tried to call any mutable methods on it.

Also, you could create a new NSString with the class method:

NSString *string = [NSString stringWithString:mutableString];

Upvotes: 4

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