How to leave a set number of spaces in NSString? - objective-c

Question

I have separate text objects for the unchanging portion (i.e. "Bonus Score: (+7%)") and the changing portion (e.g. "247,890"). Since they're separate, I want to leave space in the unchanging portion to display the number.
What I first tried was:
NSString* numberString = #"247,890";
NSString* blankScore = [#"" stringByPaddingToLength:[numberString length] withString: #" " startingAtIndex:0];
NSString* baseDisplay = [NSString stringWithFormat:#"BONUS SCORE: %# (+7%%)", blankScore];
'blankScore' was the correct length, but the resulting baseDisplay seemed to trim the spaces around where blankScore would be, making it too small of a space for the displayed number.
Next I tried another way of creating blankScore:
NSString* blankScore = [numberString stringByReplacingCharactersInRange:NSMakeRange(0, [numberString length]) withString:#" "];
But this returned a blankScore of length 1.
Am I understanding these NSString methods incorrectly? I checked the docs, and it seems like my understanding of these methods aligns with what's written there, but I still don't understand why I can't get my baseDisplay to have the correct number of spaces.

Answer 1

Have you printed blankScore on the console using NSLog? Actually your string is correct, but the output is trimmed at end of lines - this is why you see it as described.

Answer 2

#H2CO3 is on to the right solution. You should be using:
NSString *baseDisplay = [NSString stringWithFormat:#"BONUS SCORE: %# (+7%%)", numberString];
To make this work even better, you may want to consider an NSNumberFormatter to correctly format the changing part before inserting it into the baseDisplay object. Something like this:
NSNumber *changingNumber = [NSNumber numberWithDouble:247890];
NSNumberFormatter *correctFormat = [[NSNumberFormatter alloc] init];
[correctFormat setNumberStyle:NSNumberFormatterDecimalStyle];
[correctFormat setHasThousandSeparators:YES];
[correctFormat setUsesGroupingSeparator:YES];
NSString *numberString = [correctFormat stringFromNumber:changingNumber];
NSString *baseDisplay = [NSString stringWithFormat:#"BONUS SCORE: %# (+7%%)", numberString];
This way no matter what number you throw at it, it will correctly display "1,234,456" or "34,567", whatever.
EDIT:
Based on the comments to my answer you will need to use:
stringByPaddingToLength:withString:startingAtIndex:
It should look something like this:
NSString *templateString = #"BONUS SCORE:";
NSString *templateString2 = #"(+7%%)";
NSUInteger baseStringLength = [templateString length] + [numberString length];
NSString *spacedString = [templateString stringByPaddingToLength:baseStringLength withString:#" " startingAtIndex:0];
NSString *baseDisplay = [NSString stringWithFormat:#"%#%#", spacedString, templateString2];