Make a float only show two decimal places

Question

I have the value 25.00 in a float, but when I print it on screen it is 25.0000000.
How can I display the value with only two decimal places?

Answer 1

in objective -c is u want to display float value in 2 decimal number then pass argument indicating how many decimal points u want to display e.g 0.02f will print 25.00 0.002f will print 25.000

Answer 2

You can also try using NSNumberFormatter:

NSNumberFormatter* nf = [[[NSNumberFormatter alloc] init] autorelease];
nf.positiveFormat = @"0.##";
NSString* s = [nf stringFromNumber: [NSNumber numberWithFloat: myFloat]];

You may need to also set the negative format, but I think it's smart enough to figure it out.

Answer 3

Here's some methods to format dynamically according to a precision:

+ (NSNumber *)numberFromString:(NSString *)string
{
    if (string.length) {
        NSNumberFormatter * f = [[NSNumberFormatter alloc] init];
        f.numberStyle = NSNumberFormatterDecimalStyle;
        return [f numberFromString:string];
    } else {
        return nil;
    }
}

+ (NSString *)stringByFormattingString:(NSString *)string toPrecision:(NSInteger)precision
{
    NSNumber *numberValue = [self numberFromString:string];

    if (numberValue) {
        NSString *formatString = [NSString stringWithFormat:@"%%.%ldf", (long)precision];
        return [NSString stringWithFormat:formatString, numberValue.floatValue];
    } else {
        /* return original string */
        return string;
    }
}

e.g.

[TSPAppDelegate stringByFormattingString:@"2.346324" toPrecision:4];

=> 2.3453

[TSPAppDelegate stringByFormattingString:@"2.346324" toPrecision:0];

=> 2

[TSPAppDelegate stringByFormattingString:@"2.346324" toPrecision:2];

=> 2.35 (round up)

Answer 4

 lblMeter.text=[NSString stringWithFormat:@"%.02f",[[dic objectForKey:@"distance"] floatValue]];

Answer 5

The problem with all the answers is that multiplying and then dividing results in precision issues because you used division. I learned this long ago from programming on a PDP8. The way to resolve this is:

return roundf(number * 100) * .01;

Thus 15.6578 returns just 15.66 and not 15.6578999 or something unintended like that.

What level of precision you want is up to you. Just don't divide the product, multiply it by the decimal equivalent. No funny String conversion required.

Answer 6

It is not a matter of how the number is stored, it is a matter of how you are displaying it. When converting it to a string you must round to the desired precision, which in your case is two decimal places.

E.g.:

NSString* formattedNumber = [NSString stringWithFormat:@"%.02f", myFloat];

%.02f tells the formatter that you will be formatting a float (%f) and, that should be rounded to two places, and should be padded with 0s.

E.g.:

%f = 25.000000
%.f = 25
%.02f = 25.00