How do I remove leading & trailing whitespace of NSString inside an NSArray?

Question

I have an NSArray declared as such:

@property (nonatomic, strong) NSArray *arrayRefineSubjectCode;

I have the array elements manually filled out as below:

     arrayRefineSubjectCode = [NSArray arrayWithObjects:
                              @"  BKKC 2061",
                              @"   BKKS 2631   ",
                              @"BKKS 2381      ",
                              nil];

So how do I remove starting and ending whitespace and make each array elements to become as these:

     arrayRefineSubjectCode = [NSArray arrayWithObjects:
                              @"BKKC 2061",
                              @"BKKS 2631",
                              @"BKKS 2381",
                              nil];

I have tried using "stringByTrimmingCharactersInSet:" but it only works for NSString. Kinda confused here. Please help...

Answer 1

The NSArray and the contained NSString objects are all immutable. There's no way to change the objects you have.

Instead you have to create new strings and put them in a new array:

NSMutableArray *trimmedStrings = [NSMutableArray array];
for (NSString *string in arrayRefineSubjectCode) {
    NSString *trimmedString = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    [trimmedStrings addObject:trimmedString];
}
arrayRefineSubjectCode = trimmedStrings;