Develop Reference

How to print entire number even after removing decimal point?

I have a number as
Double d = 100.000000;
I want to remove the decimal point and print the values as 100000000
(Note I am using java)

It is impossible. double doesn't store zeroes after decimal point so 1.0000 is equal to 1.0.
Hint: you can use BigDecimal for this. It have scale.

I'm afraid 100.000000 does not equal 100000000 and as mentioned by #talex, double doesn't store the zeros after the decimal point.
Your best bet is to use a String and remove the . manually:
String s = "100.000000";
System.out.println(s.replaceAll("\\.", "")); //note '.' needs to be escaped
Output:
100000000
You could parse it as a Double then if necessary.

Format the value using String.format and the remove the separator.
double d = 100.000;
String formatted = String.format(
Locale.US, //Using a Locale US to be sure the decimal separator is a "."
"%5f", //A decimal value with 5decimal
d) //The value to format
.replace(".", ""); //remove the separator
System.out.println(formatted);
100000000
Other examples :
100.000123456 > 100000123
You can see that the value is truncated, it is important to understand that.
Note that I have set the String to have 5 decimal number, but this up to you.

the double does not store the number as 100.0000 it just stored as 100.0 that means any unnecessary zeros on the right will be deleted but if the number was like this 100.01234 u can use this trick
Double d = 100.01245;
String text = Double.toString(d);
text.replace(".","");
d = Double.parseDouble(text);
or u can store the number as sting from the beginning
String text = "100.000000";
d.replace(".","");
double d = Double.parseDouble(text);

format numeric currency to textual Indian number format Android

I do have some numbers like 100,000 and I want output as 1 Lakh in Indian numbering system. is there any method that supports it?
Detailed Example.
Input 5,50,000
Output 5.5 Lakh

You could try stripping the commas, casting to an integer, the dividing to get the number of Lakhs:
DecimalFormat df = new DecimalFormat("#.#####");
String input = "5,50,000";
double lakhs = Double.parseDouble(input.replaceAll(",", "")) / 100000;
String out = df.format(lakhs);
System.out.println(out);
Demo

You can use this github library:
https://github.com/fabiomsr/MoneyTextView
That is display amounts of money in different formats.

Number of digits after decimal using String.format

I know to convert a double value to string , I can do like this :
String value = String.format("%f", 10.0000);
Also I can control the number of digits after decimal using this :
String value = String.format("%.3f", 10.000000);
But my problem is that, I am receiving number of digits after decimal point through a variable.
How can I use String.format to print the number of digits after decimal provided by the user.
Regards,
Anuj

String value = String.format("%."+x+"f", 10.000000);
where x is number of digits.

Fromatting double value to 2 decimals

i want to format my double value to 2 decimals and then make it "text to speech".
this is my code:
mares = mass * acc;
DecimalFormat df = new DecimalFormat("#.00");
df.format(mares);
String mare = String.format("The force is %f", df);
home.speak(mare,TextToSpeech.QUEUE_FLUSH, null);
but it crashes, i don't know why, i put 5 and 6 and it should multiply them and give me 30.00 or something like that.
when i remove DecimalFormat the result is 30.00000000000000, i just don't like it, too many zeros.
can someone help me please?
Thanks in advance!

Your DecimalFormat is returning the formatted string, but you are ignoring it, and passing it as an argument to String.format, which certainly isn't right.
Assign the return of df.format to a string for further reference:
String mare = df.format(mares);
Or pass the numeric value directly to String.format, with the appropriate format precision specified:
String mare = String.format("The force is %.2f", mares);

Formatting in java

Good day.
I need to format a number in java.
So far I have this:
DecimalFormat df2 = new DecimalFormat( "#,###,###,##0.00" );
System.out.println(new Double(df2.format(balance)).doubleValue());
But it prints out this
110.0
121.0
133.1
146.41
161.05
But I need it to be with two digits in fraction part. How do I do it?

You don't have to get double value from formatted string.
Just use formatted string, which is returned from format() method of DecimalFormat.
So your code should be like the following:
DecimalFormat df2 = new DecimalFormat( "#,###,###,##0.00" );
...
System.out.println(df2.format(balance));
Your original code:
System.out.println(new Double(df2.format(balance)).doubleValue());
What you did in your code is: format the double value to string(which is formatted as you specified in the DecimalFormat instance). Then you convert the formatted string to Double instance and get double value from the object, which is double. And then printed it to console. So the formatted string is gone, and the double value is printed as normal.

"But I need it to be with two digits in fraction part. How do I do it?"
DecimalFormat df2 = new DecimalFormat( );
df2.setMinimumFractionDigits(2);
df2.setMaximumFractionDigits(2);
System.out.println(df2.format(balance));

You could also use the setMinimumFractionDigits method of DecimalFormat
df2.setMinimumFractionDigits(2);

your decimal format is right, but
what you are doing before you print this out is new Double(df2.format(balance)) which create new instant of double, which ignores your formatting.
so if you want to display or log your value df2.format(balance) this should be enough
ie:
System.out.println(df2.format(balance));

Try this pattern for formatting #,###,###,##.##-
DecimalFormat df2 = new DecimalFormat( "#,###,###,##.##" );
System.out.println(df2.format(balance));

This should be sufficient:
DecimalFormat df2 = new DecimalFormat("#,##0.00");
System.out.println(df2.format(balance));
The grouping for separator will follow "the interval between the last one and the end of the integer". So there is no benefit from over-specify. Example from the documentation of DecimalFormat:
The grouping separator is commonly used for thousands, but in some countries it separates ten-thousands. The grouping size is a constant number of digits between the grouping characters, such as 3 for 100,000,000 or 4 for 1,0000,0000. If you supply a pattern with multiple grouping characters, the interval between the last one and the end of the integer is the one that is used. So "#,##,###,####" == "######,####" == "##,####,####".
Another thing is that .format() method already output a String, so there is no point in converting it to double. It will cause Exception to be thrown when balance is more than 1000 (the point when separator comes into effect, and Double class cannot parse the String with separator).