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

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

Answer 2

Here are few corrections-

//for 3145.559706

---

Swift 3

let num: CGFloat = 3145.559706
print(String(format: "%f", num)) = 3145.559706
print(String(format: "%.f", num)) = 3145
print(String(format: "%.1f", num)) = 3145.6
print(String(format: "%.2f", num)) = 3145.56
print(String(format: "%.02f", num)) = 3145.56 // which is equal to @"%.2f"
print(String(format: "%.3f", num)) = 3145.560
print(String(format: "%.03f", num)) = 3145.560 // which is equal to @"%.3f"

---

Obj-C

@"%f"    = 3145.559706
@"%.f"   = 3146
@"%.1f"  = 3145.6
@"%.2f"  = 3145.56
@"%.02f" = 3145.56 // which is equal to @"%.2f"
@"%.3f"  = 3145.560
@"%.03f" = 3145.560 // which is equal to @"%.3f"

and so on...

Answer 3

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 4

I made a swift extension based on above answers

extension Float {
    func round(decimalPlace:Int)->Float{
        let format = NSString(format: "%%.%if", decimalPlace)
        let string = NSString(format: format, self)
        return Float(atof(string.UTF8String))
    }
}

usage:

let floatOne:Float = 3.1415926
let floatTwo:Float = 3.1425934
print(floatOne.round(2) == floatTwo.round(2))
// should be true

Answer 5

In Swift Language, if you want to show you need to use it in this way. To assign double value in UITextView, for example:

let result = 23.954893
resultTextView.text = NSString(format:"%.2f", result)

If you want to show in LOG like as objective-c does using NSLog(), then in Swift Language you can do this way:

println(NSString(format:"%.2f", result))

Answer 6

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 7

IN objective-c, if you are dealing with regular char arrays (instead of pointers to NSString) you could also use:

printf("%.02f", your_float_var);

OTOH, if what you want is to store that value on a char array you could use:

sprintf(your_char_ptr, "%.02f", your_float_var);

Answer 8

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 9

Another method for Swift (without using NSString):

let percentage = 33.3333
let text = String.localizedStringWithFormat("%.02f %@", percentage, "%")

P.S. this solution is not working with CGFloat type only tested with Float & Double

Answer 10

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 11

Use NSNumberFormatter with maximumFractionDigits as below:

NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.maximumFractionDigits = 2;
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:12.345]]);

And you will get 12.35

Answer 12

If you need to float value as well:

NSString* formattedNumber = [NSString stringWithFormat:@"%.02f", myFloat];
float floatTwoDecimalDigits = atof([formattedNumber UTF8String]);

Answer 13

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