Convert String to Float with Large Number

Question

Im using MPandroid chart to inflate Pie Chart, with some String JSON return

i tried to cast String value with float.parseFloat("3584907054456.48")

but it had exponent value when i log it, something like this 3584907E12

i need to get float value 3584907054456.48 is it possible ?

List<String> dataStackedSalesVolume1;
List<String> dataStackedSalesVolume2;

float[] firstDataStacked    = new float[counte];
float[] secondDataStacked   = new float[counte];

int counte  = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(1).getDataSalesVolume().size();
dataStackedSalesVolume1 = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(0).getDataSalesVolume();
dataStackedSalesVolume2 = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(1).getDataSalesVolume();

for (int i=0; i< counte; i++) {
        firstDataStacked[i]         = Float.parseFloat(dataStackedSalesVolume1.get(i));
        secondDataStacked[i]        = Float.parseFloat(dataStackedSalesVolume2.get(i));
}

i tried to get the string and put it into new list and then parse that list and put parsed value into float[]

but it the results is rounded, i need to get the full length of data without rounded

float is a floating-point number type, having fixed precision for mantissa and exponent, not suitable for storing fixed-point numbers. You won't get better precision than this type provides. — Alex Salauyou
– Alex Salauyou, Commented May 21, 2019 at 8:56
simply saying, float type has no enough space for storing mantissa 0.358490705445648 with full precision, thus it is cut to the closest value which "fits" the space---something like 0.3584907--providing such output. — Alex Salauyou
– Alex Salauyou, Commented May 21, 2019 at 9:06

Chrisvin Jem · Accepted Answer · 2019-05-21 09:30:00Z

2

Edit - The BigDecimal value can be converted to float value by using the floatValue() method. (Example - float requiredValue = bigDecimalValue.floatValue();)

Do note however that this will result in a drop in precision.

BigDecimal bigDecimalValue = new BigDecimal("3584907054456.48");
System.out.println(bigDecimalValue); //3584907054456.48

float floatValue = bigDecimalValue.floatValue();
System.out.println(floatValue); //3.58490702E12

//Formatted better to show the drop in precision.
System.out.println(String.format("%.2f", floatValue)); //3584907018240.00

Don't use float, use BigDecimal instead.

Do note that you won't be directly able to use operators such as +,-,*,etc. You'll have to use the provided methods, refer to the official documentation or an article such GeeksForGeeks articles to help you get an initial hang of it.

Sample code -

List<String> dataStackedSalesVolume1;
List<String> dataStackedSalesVolume2;

BigDecimal[] firstDataStacked    = new BigDecimal[counte];
BigDecimal[] secondDataStacked   = new BigDecimal[counte];

int counte  = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(1).getDataSalesVolume().size();
dataStackedSalesVolume1 = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(0).getDataSalesVolume();
dataStackedSalesVolume2 = merchantECommerceDataAll.getData().getMerchantECommerceTipekartuList().getMerchantECommerceTipeKartuData().get(1).getDataSalesVolume();

for (int i=0; i< counte; i++) {
        firstDataStacked[i]         = new BigDecimal(dataStackedSalesVolume1.get(i));
        secondDataStacked[i]        = new BigDecimal(dataStackedSalesVolume2.get(i));
}

edited May 21, 2019 at 9:30

answered May 21, 2019 at 8:25

Chrisvin Jem

4,0801 gold badge12 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Ferial Adrian Over a year ago

hey, thanks for responding, but i do really need float as data type in order to inflate that data into PieChart, can I convert it into float when I parsed it into big decimal ?

second Over a year ago

BigDecimal implements the java.lang.Number interface, so you can just use floatValue()

Chrisvin Jem Over a year ago

That might not necessarily be a good idea though, the conversion to float using floatValue() might result in a loss of precision as mentioned in the docs.

Chrisvin Jem Over a year ago

So, for example, System.out.println(new BigDecimal("3584907054456.48").floatValue()); would print 3.58490702E12. If we further format that, System.out.println(String.format("%.2f",new BigDecimal("3584907054456.48").floatValue())); would print 3584907018240.00. As you can see, there is precision loss.

Raso Over a year ago

Its same with float, float = 3584907054456.48f; String.format("%.2f", float); output is 3584907018240,00

|

Michael Wasser · Accepted Answer · 2019-05-21 08:27:52Z

0

You can use something like BigDecimal.valueOf(new Double("3584907054456.48")) from java.math After this you can divide, compare your value and so on

answered May 21, 2019 at 8:27

Michael Wasser

1

3 Comments

Henry Over a year ago

converting first to a double may cause rounding errors as well. There is at most as much precision as in a double. So it somehow defeats the purpose of BigDecimal.

Alex Salauyou Over a year ago

you propose the worst possible approach

Michael Wasser Over a year ago

@AlexSalauyou you're right, solution isn't really good :( Must be simpler

Collectives™ on Stack Overflow

Convert String to Float with Large Number

2 Answers 2

7 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related