I am trying to convert the value to float with 2 precision decimal format.
NSString* formattedNumber = [NSString stringWithFormat:#"%.2lu", (unsigned long)users.count];
float totalRatingCount = atof([formattedNumber UTF8String]);
This gives me values such as
1.000000
2.000000
3.000000
What I want is the following
1.00
2.00
3.00
Where am i going wrong?
A float has no precision value, it's not a fixed point value. However, there is an easier way to convert to float:
CGFloat totalRating = [formattedNumber floatValue];
to print a float with 2dp's of precision, use the format string #"%.02f"
You need to use %.2f format specifier as
NSString* formattedNumber = [NSString stringWithFormat:#"%.2f", (float)users.count];
float totalRatingCount = atof([formattedNumber UTF8String]);
and you'll get the desired out put with 2 values precision after decimal.
Using NSNumberFormatter, you can rounding number up to two digit.
double d = 12.1278;
NSNumberFormatter *formatter = [NSNumberFormatter new];
[formatter setRoundingMode:NSNumberFormatterRoundFloor];
[formatter setMinimumFractionDigits:2];
[formatter setMaximumFractionDigits:2];
NSString *numberString = [formatter stringFromNumber:#(d)];
NSLog(#"numberString: %#", numberString);
Output is :
numberString: 12.12
Try this:
NSNumber *number = [NSNumber numberWithFloat:(unsigned long)users.count];
NSNumberFormatter* nf=[[NSNumberFormatter alloc]init];
nf.minimumFractionDigits=2;
nf.maximumFractionDigits=2;
NSString* str = [nf stringFromNumber:number];
NSLog(#"%#",str);
Related
Given the NSString "1.625", I want to round this to "1.63".
How in the world do I do that?
This is what i have now:
NSString *rateString = [NSString stringWithFormat:#"%.2f", [#"1.63" doubleValue]];
NSNumberFormatter * f = [[NSNumberFormatter alloc] init];
[f setNumberStyle:NSNumberFormatterDecimalStyle];
item.rate = [f numberFromString:rateString];;
However, doubleValue converts 1.625 to 1.6249999999
So when I round it to two decimal digits with #"%.2f", I end up with 1.62!
If you wanna round to the nearest hundredths, multiply by 100, increment by .5 and divide by 100. Then get the floor of that value.
double rate = [#"1.625" doubleValue];
double roundedNumber = floor(rate * 100 + 0.5) / 100;
NSString *rateString = [NSString stringWithFormat:#"%.2f", roundedNumber];
NSLog(#"rate: %#", rateString);
Running this then outputting the result:
2015-01-13 15:41:08.702 Sandbox[22027:883332] rate: 1.63
If you need high precision what you really need is NSDecimalNumberclass maybe coupled with NSDecimalNumberHandler if don't need to configure all details, or NSDecimalNumberBehaviors if need absolute control. This is the quickest solution to keep 2 decimal digits (the 'scale' value in handler init):
NSDecimalNumberHandler *handler = [[NSDecimalNumberHandler alloc]initWithRoundingMode:NSRoundBankers
scale:2
raiseOnExactness:NO
raiseOnOverflow:NO
raiseOnUnderflow:NO
raiseOnDivideByZero:NO];
[NSDecimalNumber setDefaultBehavior:handler];
NSString *string = #"1.63";
NSDecimalNumber *number = [NSDecimalNumber decimalNumberWithString:string];
NSDecimalNumber docs:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSDecimalNumber_Class/index.html
NSDecimalNumberHandler docs:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSDecimalNumberHandler_Class/index.html
NSDecimalNumberBehaviors docs:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Protocols/NSDecimalNumberBehaviors_Protocol/index.html
I am having difficulties converting NSString's that have numbers into floats or something more useful.
I have tried the following code:
NSString *mystring = #"123"
int currentBidAmount = [myString integerValue];
No problem there.
Then float
NSString *mystring = #"123.95"
float currentBidAmount = [myString floatValue];
Again, no problem
However when myString has three decimals - I get an inaccurate number. For Example:
NSString *mystring = #"1.123.95"
float currentBidAmount = [myString floatValue];
It prints out: 1
Can someone tell me what I am doing wrong here?
The goal is to have two NSStrings - get their values and add them up for a total amount. So I need more accuracy than just I am getting now.
While you can get an NSString integer or floatValue you should use NSNumberFormatterfor that. Why? The decimal and grouping separator varies between countries and the floatValue code does only account for . as decimal separator. So users with a locale using a , are doomed.
How to:
NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
float myFloat = [numberFormatter numberFromString:myString].floatValue;
Read up on various settings here: https://developer.apple.com/library/ios/documentation/cocoa/reference/foundation/classes/NSNumberFormatter_Class/Reference/Reference.html
you can't put two commas for a float value
this code works fins:
NSString *example = #"13124.4153";
float floatValue = [example floatValue];
NSLog(#"value = %f", floatValue);
Thanks for the help guys. I managed to solve the problem. The issue was the grouping separator. It separated by leaving a space. So this is why I had inaccurate numbers. Now, since I needed all my numbers to stay in this format but change when I was doing calculations (Adding sums together - I wrote a class method that looks like this:
(NSString *)getDisplayAmountStringWithValue: (NSString *)value Currency: (NSString *)currency
{
NSDecimalNumber *decimalValue = [NSDecimalNumber decimalNumberWithString:[value stringByReplacingOccurrencesOfString:#"," withString:#""]];
if ([decimalValue isEqualToNumber:[NSDecimalNumber notANumber]]){
decimalValue = [NSDecimalNumber decimalNumberWithString:#"0"];
}
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setGroupingSeparator:#" "];
[formatter setDecimalSeparator:#"."];
[formatter setMaximumFractionDigits:2];
[formatter setMinimumFractionDigits:2];
if ([currency length] > 0){
[formatter setPositivePrefix:[NSString stringWithFormat:#"%#", currency]];
[formatter setNegativePrefix:[NSString stringWithFormat:#"%#-", currency]];
}else {
[formatter setGroupingSeparator:#""];
}
NSString *newNumberString = [formatter stringFromNumber:decimalValue];
return newNumberString;
}
Notice the if statement. I simply remove the space if I don't supply a currency (Which is not needed when adding sums together) - this along with my existing code, works perfectly.
Thanks for all the tips.
Yes. You are right. Of Course this is a duplicate question. Before flag my question, please continue reading below.
I want to round a float value, which is
56.6748939 to 56.7
56.45678 to 56.5
56.234589 to 56.2
Actually it can be any number of decimal precisions. But I want to round it to nearest value. (If it is greater than or equal to 5, then round up and if not, then round down).
I can do that with the below code.
float value = 56.68899
NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc]init];
[numberFormatter setMaximumFractionDigits:1];
[numberFormatter setRoundingMode:NSNumberFormatterRoundUp];
NSString *roundedString = [numberFormatter stringFromNumber:[NSNumber numberWithFloat:value]];
NSNumber *roundedNumber = [NSNumber numberFromString:roundedString];
float roundedValue = [roundedNumber floatValue];
Above code looks like a long process. I have several numbers to round off. So this process is hard to convert a float value into NSNumber and to NSString and to NSNumber and to float.
Is there any other easy way to achieve what I asked ?
I still have a doubt in the above code. It says roundUp. So when it comes to roundDown, will it work?
Can't you simply multiply by 10, round the number, then divide by 10?
Try
CGFloat float1 = 56.6748939f;
CGFloat float2 = 56.45678f;
NSLog(#"%.1f %.1f",float1,float2);
56.7 56.5
EDIT :
float value = 56.6748939f;
NSString *floatString = [NSString stringWithFormat:#"%.1f",floatValue];
float roundedValue = [floatString floatValue];
NSString* strr=[NSString stringWithFormat: #"%.1f", 3.666666];
NSLog(#"output is: %#",strr);
output is:3.7
float fCost = [strr floatValue];
This works for me
NSNumberFormatter* formatter = [[NSNumberFormatter alloc] init];
[formatter setMaximumFractionDigits:1];
[formatter setMinimumFractionDigits:0];
CGFloat firstnumber = 56.6748939;
NSString *result1 = [formatter stringFromNumber:[NSNumber numberWithFloat:firstnumber]];
NSLog(#"RESULT #1: %#",result1);
CGFloat secondnumber = 56.45678;
NSString *result2 = [formatter stringFromNumber:[NSNumber numberWithFloat:secondnumber]];
NSLog(#"RESULT #2: %#",result2);
CGFloat thirdnumber = 56.234589;
NSString *result3 = [formatter stringFromNumber:[NSNumber numberWithFloat:thirdnumber]];
NSLog(#"RESULT #2: %#",result3);
You don't want float, because that only gives you six or seven digits precision. You also don't want CGFloat, because that only gives you six or seven digits precision except on an iPad Air or iPhone 5s. You want to use double.
Rounding to one digit is done very simply:
double x = 56.6748939;
double rounded = round (10 * x) / 10;
You can use
[dictionaryTemp setObject:[NSString stringWithFormat:#"%.1f",averageRatingOfAllOrders] forKey:#"AvgRating"];
%.1f will give us value 2.1 only one digit after decimal point.
Try this :
This will round to any value not limited by powers of 10.
extension Double {
func roundToNearestValue(value: Double) -> Double {
let remainder = self % value
let shouldRoundUp = remainder >= value/2 ? true : false
let multiple = floor(self / value)
let returnValue = !shouldRoundUp ? value * multiple : value * multiple + value
return returnValue
}
}
When I convert NSNumber to float value using 'floatValue', there is a difference in precision. Example, I have a NSNumber 'myNumber' having value 2.3, and if I convert myNumber to float using 'floatValue', its value becomes, 2.29999. But I need exactly 2.30000. There is no problem with number of zeros after 2.3, I need '2.3' instead of '2.9'.
How can I do so?
I had similar situation where I was reading value and assigning it back to float variable again.
My Problem statement:
NSString *value = #"553637.90";
NSNumber *num = #([value floatValue]); // 1. This is the problem. num is set to 553637.875000
NSNumberFormatter *decimalStyleFormatter = [[NSNumberFormatter alloc] init];
[decimalStyleFormatter setMaximumFractionDigits:2];
NSString *resultString = [decimalStyleFormatter stringFromNumber:num]; // 2. string is assigned with rounded value like 553637.88
float originalValue = [resultString floatValue]; // 3. Hence, originalValue turns out to be 553637.88 which wrong.
Following worked for me after changing lines:
NSNumber *num = #([value doubleValue]); // 4. doubleValue preserves value 553637.9
double originalvalue = [resultString doubleValue]; // 5. While reading back, assign to variable of type double, in this case 'originalValue'
I hope this would be helpful. :)
If you need exact precision, don't use float. Use a double if you need better precision. That still won't be exact. You could multiply myNumber by 10, convert to an unsigned int and perform your arithmetic on it, convert back to a float or double and divide by 10 and the end result might be more precise. If none of these are sufficiently precise, you might want to look into an arbitrary precision arithmetic library such as GNU MP Bignum.
I've done the following but it is showing me correctly
NSNumber *num = [NSNumber numberWithFloat:2.3];
float f = [num floatValue];
NSLog(#"%f", f);
You can play with something like this:
float x = 2.3f;
NSNumber *n = [NSNumber numberWithFloat:x];
NSNumberFormatter *fmt = [[NSNumberFormatter alloc] init];
[fmt setPositiveFormat:#"0.#"];
NSString *s = [fmt stringFromNumber:n];
float f = [s floatValue];
In Java we do this statement to have a $ currency format.
double num1 = 3.99 ;
double num2 = 1.00 ;
double total = num1 + num2;
System.out.printf ("Total: $ %.2f", total);
The result is:
Total: $4.99
//--------------------------------
Now in iOS how can I get same format if I have the following statement :
total.text = [NSString stringWithFormat:#"$ %d",([self.coursePriceLabel.text intValue])+([self.courseEPPLabel.text intValue])+10];
Note:
If I use doubleValue the output always is 0 .
You can do the same thing with NSString:
NSString *someString = [NSString stringWithFormat:#"$%.2lf", total];
Note that the format specifier is "%lf" rather than just "%f".
But that only works for US dollars. If you want to make your code more localizable, the right thing to do is to use a number formatter:
NSNumber *someNumber = [NSNumber numberWithDouble:total];
NSNumberFormatter *nf = [[NSNumberFormatter alloc] init];
[nf setNumberStyle:NSNumberFormatterCurrencyStyle];
NSString *someString = [nf stringFromNumber:someNumber];
Of course, it won't do to display a value calculated in US dollars with a Euro symbol or something like that, so you'll either want to do all your calculations in the user's currency, or else convert to the user's currency before displaying. You may find NSValueTransformer helpful for that.