Reading a file into array with mutable array in Objective C

Question

I'm trying to read a file into array, by using mutable array in Objective C like this:

NSCharacterSet *newlineCharSet = [NSCharacterSet newlineCharacterSet];
NSMutableArray *myStr = [data componentSeparatedByCharactersInSet: newlineCharSet];

And this is the warning that I've got :

Incompatible pointer type initializing "NSMutableArray" with an expression of type "NSArray"

The reason why I used NSMutableArray is because later I'm going to convert all the elements inside the array to lowercase. Would it be possible to fix the warning and still satisfy the condition to use mutable array ? Thank you.

James Frost · Accepted Answer · 2014-09-08 08:26:45Z

4

componentsSeparatedByCharactersInSet: returns an NSArray, not a mutable array. To satisfy the compiler (and actually provide you with a mutable array), simple create a mutable copy:

NSMutableArray *myStr = [[data componentsSeparatedByCharactersInSet:newlineCharSet] mutableCopy];

answered Sep 8, 2014 at 8:26

James Frost

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Asif Mujteba · Accepted Answer · 2014-09-08 08:43:59Z

3

componentSeparatedByCharactersInSet returns an NSArray object.. If you want an NSMutableArray Object instead than you need to create an NSMutableArray from it like this:

NSMutableArray *myStr = [NSMutableArray arrayWithArray:[data componentSeparatedByCharactersInSet: newlineCharSet]];

edited Sep 8, 2014 at 8:43

answered Sep 8, 2014 at 8:25

Asif Mujteba

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