What are the applications of copy and mutableCopy in actual projects?

Question

NSString *str1 = @"test";
[str1 copy];

NSMutableString *mStr1 = [NSMutableString stringWithString:@"test002"];
[mStr1 mutableCopy];

NSArray *arry1 = [[NSArray alloc] initWithObjects:@"value1", @"value2",nil];
[arry1 copy];

NSMutableArray *marry1 = [[NSMutableArray alloc] initWithObjects:@"value1", 
@"value2",nil];
[marry1 mutableCopy];

I know the different for them, but I want to know how to use them in the actual projects. — Sunny_Ken, Nov 04 '17 at 08:04
What do you mean about using them in the actual projects. That link provides all of their effect and how to use them. — trungduc, Nov 04 '17 at 08:10

score 1 · Accepted Answer · answered Nov 04 '17 at 08:13

1

NSArray *arry1 = [[NSArray alloc] initWithObjects:@"value1", @"value2",nil];
NSArray * testCopyArray =  [arry1 copy];  // returns immutable copy of array
NSMutableArray * testMutableCopyArray = [arry1 mutableCopy]; //// returns mutable copy of array
[testMutableCopyArray addObject:@"value3"]; // you can modify its values

If you are facing use cases like you want to modify a NSArray value , you can assign its mutable copy to a NSMutableArray and modify it.

answered Nov 04 '17 at 08:13

Anshad Rasheed

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yep! so mutableCopy can use to exchange immutable to mutable object. – Sunny_Ken Nov 04 '17 at 08:42
And how do you mutable exchange to immutable object? – Sunny_Ken Nov 04 '17 at 08:43

What are the applications of copy and mutableCopy in actual projects?

1 Answers1