Floating numbers

Ned Deily nad at acm.org
Fri Aug 13 03:14:10 CEST 2010


In article <i41p6e$1fg$1 at dough.gmane.org>,
 Christian Heimes <lists at cheimes.de> wrote:
>> Is there a way I can keep my floating point number as I typed it? For
>> example, I want 34.52 to be 34.52 and NOT 34.5200000002. 
> This isn't a Python issue. Python uses IEEE 754 [1] double precision
> floats like most other languages. 34.52 can't be stored in a float. The
> next valid float is 34.5200000002.

Well, it is a *bit* of a Python issue since, as others have pointed out, 
Python's behavior has changed due to the implementation of Gay's 
rounding algorithm in 3.1 and also in 2.7:

$ python2.6 -c 'print(repr(34.52))'
34.520000000000003
$ python2.7 -c 'print(repr(34.52))'
34.52
$ python3.1 -c 'print(repr(34.52))'
34.52

-- 
 Ned Deily,
 nad at acm.org




More information about the Python-list mailing list