iOS: changing NSString value

Question

Will this bit of code produce any memory leaks? Is it the correct way to change NSString values?

NSString * enemiesAndElementsTextureFileName = @"bla bla";
enemiesAndElementsTextureFileName = @"bl";

It won't produce memory leak. It is valid code and is a very common usage, so you might want to clarify yourself why you doubt anything could go wrong with that. — tia
– tia, Commented Jun 9, 2013 at 14:45

jfuellert · Accepted Answer · 2013-06-09 14:37:44Z

3

That way of doing it won't cause any memory leaks and it is indeed correct. In this case you wouldn't need an NSMutableString because you aren't altering the string literal itself, you are simply replacing the string value with a new one (replacing @"bla bla" with @"bl").

In this case, however, your string will now be 'bl', so you can delete that first line value and just have NSString * enemiesAndElementsTextureFileName = @"bl";

answered Jun 9, 2013 at 14:37

jfuellert

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Prateek Prem · Accepted Answer · 2013-06-09 14:23:26Z

1

Yes NSString allocated once. This is one of the way

answered Jun 9, 2013 at 14:23

Prateek Prem

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2 Comments

mm24 Over a year ago

...are you saying "yes is correct" or "yes it will produce memory leaks"? I assume the first option. So the previous string will not be leaked in memory somewhere ?

Anupdas Over a year ago

Even if it was not allocated, literal @"foo" is literally equal to [[NSString alloc]initWithString:@"foo"];

malajisi · Accepted Answer · 2014-08-07 11:38:00Z

1

Yes, use NSMutableString with the following method as your needs:

// Allocate  
NSMutableString *str = [[NSMutableString alloc] initWithCapacity:10];  
// set string content  
[str setString:@"1234"];  

// Append  
[str appendString:@"567"];  

// Concat  
[str appendFormat:@"age is %i and height is %.2f", 27, 1.55f];  

// Replace 
NSRange range = [str rangeOfString:@"height"];//查找字符串height的位置  
[str replaceCharactersInRange:range withString:@"no"];  

// Insert  
[str insertString:@"abc" atIndex:2];  

// Delete  
range = [str rangeOfString:@"age"];  
[str deleteCharactersInRange:range];  
NSLog(@"%@", str);

answered Aug 7, 2014 at 11:38

malajisi

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