converting from BigDecimal to BigInteger

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Jeremy Watts - 17 Feb 2007 17:44 GMT

I am trying to convert a BigDecimal number to a BigInteger one. I have
truncated the number to its nearest whole integer firstly, before converting
it to a string and then converting that to a BigInteger.... but the
compilers coming back with an error message "Number Format Exception".

Cant see what I'm doing wrong here... The number I'm using for the
BigDecimal is
'465836768828.000' . Is it the ".000" bit thats messing things up here?
How would I remove that so that I'm left with 465836768828 ?

Or is there a better way of converting between the two?

Thanks

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Lothar Kimmeringer - 17 Feb 2007 17:57 GMT

> Or is there a better way of converting between the two?

RTFM[1]

BigInteger bi = mybigdecimal.toBigInteger();

Regards, Lothar

[1] http://java.sun.com/j2se/1.3/docs/api/java/math/BigDecimal.html

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Jeremy Watts - 17 Feb 2007 18:10 GMT

> > Or is there a better way of converting between the two?
>
> RTFM[1]
>
> BigInteger bi = mybigdecimal.toBigInteger();

hee hee that simple eh? :) I'm sure I'd done this before somewhere
without converting to strings first... anyway thanks

> Regards, Lothar
>
[quoted text clipped - 5 lines]
> Always remember: The answer is forty-two, there can only be wrong
> questions!

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Patricia Shanahan - 17 Feb 2007 18:21 GMT

> I am trying to convert a BigDecimal number to a BigInteger one. I have
> truncated the number to its nearest whole integer firstly, before converting
[quoted text clipped - 5 lines]
> '465836768828.000' . Is it the ".000" bit thats messing things up here?
> How would I remove that so that I'm left with 465836768828 ?

Yes, the "." is not a permitted character: "The String representation
consists of an optional minus sign followed by a sequence of one or more
decimal digits."

> Or is there a better way of converting between the two?

I half agree with the toBigInteger suggestion. If you expect your
BigDecimal to always be an integer, you could use toBigIntegerExact,
which throws an exception on data loss.

Patricia

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Lothar Kimmeringer - 17 Feb 2007 18:34 GMT

> I half agree with the toBigInteger suggestion. If you expect your
> BigDecimal to always be an integer, you could use toBigIntegerExact,
> which throws an exception on data loss.

He didn't mention the Version of Java the program should work.
toBigIntegerExact exists since 1.5.

Regards, Lothar

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converting from BigDecimal to BigInteger

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