I have got a float value which is supposed to have a certain number of decimal places. The number of decimal places is stored in a variable.
Here is the line of code:
self.numberTextField.text = [NSString stringWithFormat:@"%.%df",result, [[NSUserDefaults standardUserDefaults] boolForKey:@"decimalPlaces"]];
My problem is that I do not know how to combine the %f and %d specifiers in the right way. Any ideas?
Thank for your answer!
You can replace a field width or precision by an asterisk (*) and it will then pick up the value from the parameter list.
int width = 5;
int precision = 2;
double value = 3.1415926;
NSString* formattedNumber = [NSString stringWithFormat: @"%*.*f", width, precision, value];
http://pubs.opengroup.org/onlinepubs/009695399/functions/printf.html
Consider also using an NSNumberFormatter. It has the advantage of being Internationalisation aware.
I think you will have to do this in 2 stages
first create the formatted string with the desired number of decimal points:
NSString *format = [NSSString stringWithFormat:@"%%.%if", numberOfPlaces];
%% is an escaped percentage so the only part that will be replaced in the format will be %i, i.e. numberOfPlaces = 2 will give format = @"%.2f"
Then you use that format string to create the end result
NSString *valueString = [NSString stringWithFormat:format, myLongFloat];
