[Python-Dev] rounding problem (original) (raw)

Tony Meyer t-meyer at ihug.co.nz
Mon May 31 21:41:27 EDT 2004

[I think this would be better in python-list, not python-dev]

the number actually comes from multiplication between 237.50 and 4.762 which will get 1130.975. So it suppose to be 1130.98 isnt it if it'll get rounded to 2 decimal places.

Gary is correct:

237.50 * 4.762 1130.9749999999999 round(,2) 1130.97 print 237.50 * 4.762 1130.975

The answer correctly rounds to 1130.97 because the next digit is 4, not 5. When you print it, it rounds to 3 decimal places, so you get the .9749 rounding to .975.

This is just floating point arithmetic. You might want to try the Decimal module, or something like that, to avoid this.

=Tony Meyer

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