Rounding the decimal part of a real number
Dear sir, Is there any function for rounding the real number, for "n" (say) decimal places: Example: Let X= 6.9867349234888211237767867863478728314... but i need only 4 decimal position. That is the answer should be..
answer=6.9867
-- DILEEPKUMAR. R J R F, IIT DELHI
On 4/6/2011 9:14 AM, dileep kunjaai wrote:
Is there any function for rounding the real number, for "n" (say) decimal places:
http://www.google.com/search?q=numpy+round produces http://docs.scipy.org/doc/numpy/reference/generated/numpy.round_.html Cheers, Alan Isaac
On 4/6/11 6:24 AM, Alan G Isaac wrote:
http://docs.scipy.org/doc/numpy/reference/generated/numpy.round_.html
simple enough, of course, but just to be clear: In [108]: np.round(1.23456789, 3) Out[108]: 1.2350000000000001 so the number is rounded to the requested number of decimal places, but then stored in a binary floating point format, which may not be able to exactly represent that rounded number -- hence the "1" at the end. This is simply how floating point works. and that slight difference _probably_ doesn't matter, but it's worth being aware of, because is does make a difference occasionally. python has a decimal type that can work with exact decimal numbers -- numpy doesn't support that, as there is no hardware support for it (at least on most platforms). If you want to display it differently, you can use the string formatters: In [110]: "%.3f"%np.round(1.23456789, 3) Out[110]: '1.235' HTH, Chris -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov
Thank you sir........... thank you very much............. On Wed, Apr 6, 2011 at 9:36 PM, Christopher Barker <Chris.Barker@noaa.gov>wrote:
On 4/6/11 6:24 AM, Alan G Isaac wrote:
http://docs.scipy.org/doc/numpy/reference/generated/numpy.round_.html
simple enough, of course, but just to be clear:
In [108]: np.round(1.23456789, 3) Out[108]: 1.2350000000000001
so the number is rounded to the requested number of decimal places, but then stored in a binary floating point format, which may not be able to exactly represent that rounded number -- hence the "1" at the end. This is simply how floating point works.
and that slight difference _probably_ doesn't matter, but it's worth being aware of, because is does make a difference occasionally.
python has a decimal type that can work with exact decimal numbers -- numpy doesn't support that, as there is no hardware support for it (at least on most platforms).
If you want to display it differently, you can use the string formatters:
In [110]: "%.3f"%np.round(1.23456789, 3) Out[110]: '1.235'
HTH, Chris
-- Christopher Barker, Ph.D. Oceanographer
Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception
Chris.Barker@noaa.gov _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
-- DILEEPKUMAR. R J R F, IIT DELHI
participants (3)
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Alan G Isaac -
Christopher Barker -
dileep kunjaai