How do you dynamically format a number to have commas in a UITextField entry?

Question

I want to have commas dynamically added to my numeric UITextField entry while the user is typing.

For example: 123,456 and 12,345,678

Answer 1

Format the number with grouping attributes as shown here.

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setGroupingSeparator:@","];
[numberFormatter setGroupingSize:3];
[numberFormatter setDecimalSeparator:@"."];
[numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
[numberFormatter setMaximumFractionDigits:3];
[numberFormatter setMinimumFractionDigits:3];

Output for the above code is

1,234,567.850