Need Help Rounding Numbers (Float) - objective-c

In the following code, I want the the number that satisfies if (isKgs) to be rounded to one decimal point.
For example right now it is giving me 2.2643534543 but I just want 2.3.
Any ideas?
NSNumber *weightInPounds = [self.pickerArray objectAtIndex:row];
NSNumber *weightInKilos = [[DDUnitConverter massUnitConverter] convertNumber: weightInPounds fromUnit: DDMassUnitUSPounds toUnit: DDMassUnitKilograms];
NSString *temp = [NSString stringWithFormat:#"%# kgs", [weightInKilos stringValue]];
[self.firstComponentText setString:temp];
The the type of number from the picker is float, I believe.

You can format the NSNumber object using an NSNumberFormatter object. An example,
NSNumber * decimal = [NSNumber numberWithFloat:2.2643534543];
NSNumberFormatter * formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setRoundingMode:NSNumberFormatterRoundHalfUp];
[formatter setMaximumFractionDigits:1];
NSLog(#"%#", [formatter stringFromNumber:decimal]);

Related

Objective C remove trailing zeros after decimal place

I am trying to get number in 2 decimal places with trailing zeros.
e.g
11.633-> 11.63
11.630-> 11.63
11.60-> 11.6
11-> 11
12928.98-> 12928.98
for this I written below line
#define kFloatFormat2(x) [NSString stringWithFormat:#"%g", [[NSString stringWithFormat:#"%.2f", x] floatValue]]
NSNumber *number1 = [NSNumber numberWithDouble:12928.98];
NSLog(#"number1:%#", number1);
NSString *string1 = kFloatFormat2([number1 floatValue]);
NSLog(#"string1:%#", string1);
the output of above prints
number1:12928.98
string1:12929
Why it prints 12929 value for string1
I want it as 12928.98.
Have you tried using a number formatter?
NSNumberFormatter *formatter = [[NSNumberFormatter alloc]init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setUsesGroupingSeparator:NO];
[formatter setMaximumFractionDigits:fractionDigits];
[formatter setMinimumFractionDigits:fractionDigits];
Now do something like
NSNumber *x = #23423;
NSString *value = [formatter stringFromNumber:x];
NSLog(#"number = %#, value);
You macro makes no sense. Just make it:
#define kFloatFormat2(x) [NSString stringWithFormat:#"%.2f", [x floatValue]]
where x is an NSNumber. And then you would call it like this:
NSString *string1 = kFloatFormat2(number1);
Or just do this:
double x = 12928.98;
NSLog(#"number = %.2f", x);

NSNumberFormatter: Displaying zero as last digit starting from a string like 25.0

I have a string that represents a float, for example 2400.0. I want to format it as digit (2,400.0) and I need to keep the zero after the digit symbol.
NSString* theString = #"2400.0";
// I convert the string to a float
float f = [theString floatValue];
// here I lose the digit information :( and it ends up with 2400 instead of 2400.0
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setUsesSignificantDigits:YES];
[formatter setMinimumFractionDigits:1];
[formatter setMaximumFractionDigits:2];
[formatter setLocale:[NSLocale currentLocale]];
NSString *result = [formatter stringFromNumber:#(f)];
The NSLog of result is 2,400 while I need 2,400.0
How can I obtain the right string?
You probably want to set the minimumFractionDigits to 1 (and your maximumFractionDigits as well in this case).
You also probably don't want to use significant digits. The following code yields the desired output:
NSString *theString = #"2400.0";
float f = [theString floatValue];
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setMinimumFractionDigits:1];
[formatter setMaximumFractionDigits:1];
[formatter setLocale:[NSLocale currentLocale]];
NSLog(#"%#", [formatter stringFromNumber:#(f)]);
Te below solves the issue
NSString *formatString = #"0,000.0";
[formatter setPositiveFormat:formatString];
The number of 0's after decimal will be used for formatting. It works for negative numbers also.
you should dynamically change the format string based on number of digits of the float value before and after decimal point.
Hope it helps.
easy,
then you go to display it just do this:
myLabel.text = #"%0.1f", f;
Use minimumFractionDigits in addition to maximumFractionDigits:
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.minimumFractionDigits = 1;
formatter.maximumFractionDigits = 1;
XCTAssert([[formatter stringFromNumber:#(2400.0)] isEqualToString:#"2400.0"]);
XCTAssert([[formatter stringFromNumber:#(2400.1)] isEqualToString:#"2400.1"]);

NSNumberFormatter, appending decimal to calculator from UI

Ok, so I am writing a calculator app now. So far, I'm not having much luck in regard to decimals (my most recent approach hasn't worked well).
-(void) DecimalAdded
{
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setAlwaysShowsDecimalSeparator:YES];
[formatter setGeneratesDecimalNumbers:YES];
[formatter setDecimalSeparator:#"."];
//first convert the float value of CN into NSnumber
NSNumber *nextstepNumFromCNF= [NSNumber numberWithFloat:currentNumber];
//now we have to convert that number into a string
NSString *CNconverted = [formatter stringFromNumber:nextstepNumFromCNF];
NSNumber *CNdecmAddedAndReadyForPars = [formatter numberFromString:CNconverted];
currentNumber = currentNumber*10 + [CNdecmAddedAndReadyForPars floatValue];
CalculatorScreen = [NSMutableString stringWithFormat: #"%#", CNconverted];
I can append the string to the Calculator screen I can say the number is 1, I see "1." as I'm typing. However this is usually converted to 1 during th float conversion (which is correct).
What is this best way to accomplish this?

NSNumberFormatter leading 0's and decimals

Is there any way to format an NSNumber with leading 0's and decimals? For example, I need to have the ability to write 4.5 as well as 000. Currently I have it where it will allow decimals, but not leading 0's.
NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;
NSString *myString = [f numberFromString:#"4.5"];
NSLog(#"myString: %#",myString);
NSString *myOtherString = [f numberFromString:#"000"];
NSLog(#"myOtherString:%#",myOtherString);
The output from above would be: 'myString:4.5' and 'myOtherString:0'. I need to be able to do both '4.5' and '000' as output.
I have looked at Apple's "Data Formatting Guide" without much success.
Note that [f numberFromString:#"4.5"] returns an NSNumber* not a NSString*
You want something like this:
NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;
NSNumber *myNumber;
NSString *myString;
myNumber = [f numberFromString:#"4.5"];
[f setNumberStyle:kCFNumberFormatterDecimalStyle];
myString = [f stringFromNumber:myNumber];
NSLog(#"myString: %#",myString);
myNumber = [f numberFromString:#"000"]; // Note that the extra zeros are useless
[f setFormatWidth:3];
[f setPaddingCharacter:#"0"];
myString = [f stringFromNumber:myNumber];
NSLog(#"myString: %#",myString);
NSLog output:
myString: 4.5
myString: 000
If you don't have strings to start with just create number like:
myNumber = [NSNumber numberWithFloat:4.5];
myNumber = [NSNumber numberWithInt:0];
Or just use standard formatting:
myString = [NSString stringWithFormat:#"%.1f", [myNumber floatValue]];
myString = [NSString stringWithFormat:#"%03d", [myNumber intValue]];
Or if you don't need an NSNumber representation just use standard formatting :
myString = [NSString stringWithFormat:#"%.1f", 4.5];
myString = [NSString stringWithFormat:#"%03d", 0];
You could try something like:
NSString *myString = [NSString stringWithFormat:#"%03f", [myNSNumber floatValue]];
This, following the printf format, will print your number forcing at least 3 digits to be printed and padding with '0's any empty space.
How about this as a variation on theme for the 000's
NSNumber *myNumber;
NSString *myString =#"000" ;
NSString * myStringResult;
NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;
[f setHasThousandSeparators:FALSE]; //-- remove seperator
[f setMinimumIntegerDigits:[myString length ]]; //-- set minimum number of digits to display using the string length.
myNumber = [f numberFromString:myString];
myStringResult = [f stringFromNumber:myNumber];
NSLog(#"myStringResult: %#",myStringResult);
Since this is asked often and Apple's docs suck, this is the answer that people will be looking for. The link below has two solutions. One using NSString stringWithFormat: and the other using NSNumberFormatter.
https://stackoverflow.com/a/11131497/1058199

How to add commas to number every 3 digits in Objective C?

If I have a number int aNum = 2000000 how do I format this so that I can display it as the NSString 2,000,000?
Use NSNumberFormatter.
Specifically:
NSNumberFormatter *formatter = [NSNumberFormatter new];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle]; // this line is important!
NSString *formatted = [formatter stringFromNumber:[NSNumber numberWithInteger:2000000]];
[formatter release];
By default NSNumberFormatter uses the current locale so the grouping separators are set to their correct values by default. The key thing is to remember to set a number style.
Don't do your own number formatting. You will almost certainly not get all the edge cases right or correctly handle all possible locales. Use the NSNumberFormatter for formatting numeric data to a localized string representation.
You would use the NSNumberFormatter instance method -setGroupingSeparator: to set the grouping separator to #"," (or better yet [[NSLocale currentLocale] objectForKey:NSLocaleGroupingSeparator]; thanks #ntesler) and -setGroupingSize: to put a grouping separator every 3 digits.
There's a static method on NSNumberFormatter that does just what you need:
int aNum = 2000000;
NSString *display = [NSNumberFormatter localizedStringFromNumber:#(aNum)
numberStyle:NSNumberFormatterDecimalStyle];
This way is a little more succinct than creating a new NSNumberFormatter if you don't need to do any additional configuration of the formatter.
Even easier:
NSNumber *someNumber = #(1234567890);
NSString *modelNumberString = [NSString localizedStringWithFormat:#"%#", someNumber];
NSLog(#"Number with commas: %#", modelNumberString);
coworker just taught me this today. #amazing
Think some as i will get this post looking for sample.
So if you are working with number make attention on next params:
setNumberStyle:NSNumberFormatterCurrencyStyle // if you are working with currency
It could be also
setNumberStyle:NSNumberFormatterDecimalStyle
All code is For ARC.
If you are working with Integer and need to get result such as 200,000
int value = 200000;
NSNumberFormatter * formatter = [NSNumberFormatter new];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
NSString * newString = [formatter stringFromNumber:[NSNumber numberWithInteger:value]];
If you are working with Float and need to get result such as 200,000.00
float value = 200000;
NSNumberFormatter * formatter = [NSNumberFormatter new];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setMaximumFractionDigits:2]; // Set this if you need 2 digits
NSString * newString = [formatter stringFromNumber:[NSNumber numberWithFloat:value]];
EDIT
To have ability to use different digital separators use NSLocale.
Add to code where NSLocale is specified on Locale Identifier:
[formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"de_DE"]];
or use current local:
[formatter setLocale:[NSLocale currentLocale]];
Swift version
let formatter = NSNumberFormatter()
formatter.numberStyle = .DecimalStyle
formatter.maximumFractionDigits = decimalPlaces
let result = formatter.stringFromNumber(NSNumber(double: 8.0))
By http://ios.eezytutorials.com
An easy solution could be this. My answer is almost same like #Nazir's answer but with a small trick.
double current_balance = 2000000.00;
NSNumberFormatter * formatter = [NSNumberFormatter new];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
//[formatter setNumberStyle:NSNumberFormatterCurrencyStyle]; //if you want for currency with $ sign
[formatter setMinimumFractionDigits:2]; // Set this if you need 2 digits
[formatter setMaximumFractionDigits:2]; // Set this if you need 2 digits
NSString * currency_format = [NSString stringWithFormat:#"%#", [formatter stringFromNumber:[NSNumber numberWithDouble:current_balance]]];
For Swift 4.0
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
formatter.minimumFractionDigits = 2
formatter.maximumFractionDigits = 2
let result = formatter.string(from: NSNumber(value: 123456))
For those who need to do it with strings of numbers and not just integers (I.e. Big Numbers) I made the following macro:
#define addCommas(__string) (\
(^NSString *(void){\
NSString *__numberString = __string;\
NSString *__integerPortion = __numberString;\
NSString *__decimalPortion = #"";\
if ([__string containsString:#"."]) {\
__integerPortion = [__numberString componentsSeparatedByString:#"."][0];\
__decimalPortion = st(#".%#", [__numberString componentsSeparatedByString:#"."][1]);\
}\
int __i = (int)__integerPortion.length-3;\
while (__i > 0) {\
__integerPortion = st(#"%#,%#", substringInRange(__integerPortion, 0, __i), substringInRange(__integerPortion, __i, (int)__integerPortion.length));\
__i -= 3;\
}\
__numberString = st(#"%#%#", __integerPortion, __decimalPortion);\
return __numberString;\
})()\
)