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author | Mark Dickinson <dickinsm@gmail.com> | 2009-11-24 14:27:02 (GMT) |
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committer | Mark Dickinson <dickinsm@gmail.com> | 2009-11-24 14:27:02 (GMT) |
commit | 6b87f117caba3a6af28f0d0afb05515ae8997620 (patch) | |
tree | 73b2396c2562f2c64355df5cad7a3771b5360bd8 /Doc/tutorial | |
parent | 9a03f2fd03278d2c12dfe253de1bbed7c0c9c506 (diff) | |
download | cpython-6b87f117caba3a6af28f0d0afb05515ae8997620.zip cpython-6b87f117caba3a6af28f0d0afb05515ae8997620.tar.gz cpython-6b87f117caba3a6af28f0d0afb05515ae8997620.tar.bz2 |
Fix some documentation examples involving the repr of a float.
Diffstat (limited to 'Doc/tutorial')
-rw-r--r-- | Doc/tutorial/floatingpoint.rst | 2 | ||||
-rw-r--r-- | Doc/tutorial/inputoutput.rst | 8 | ||||
-rw-r--r-- | Doc/tutorial/stdlib2.rst | 9 |
3 files changed, 11 insertions, 8 deletions
diff --git a/Doc/tutorial/floatingpoint.rst b/Doc/tutorial/floatingpoint.rst index 29c7a66..3554e4f 100644 --- a/Doc/tutorial/floatingpoint.rst +++ b/Doc/tutorial/floatingpoint.rst @@ -115,7 +115,7 @@ Another consequence is that since 0.1 is not exactly 1/10, summing ten values of ... sum += 0.1 ... >>> sum - 0.99999999999999989 + 0.9999999999999999 Binary floating-point arithmetic holds many surprises like this. The problem with "0.1" is explained in precise detail below, in the "Representation Error" diff --git a/Doc/tutorial/inputoutput.rst b/Doc/tutorial/inputoutput.rst index 0259749..8d23cc1 100644 --- a/Doc/tutorial/inputoutput.rst +++ b/Doc/tutorial/inputoutput.rst @@ -49,10 +49,10 @@ Some examples:: 'Hello, world.' >>> repr(s) "'Hello, world.'" - >>> str(0.1) - '0.1' - >>> repr(0.1) - '0.10000000000000001' + >>> str(1.0/7.0) + '0.142857142857' + >>> repr(1.0/7.0) + '0.14285714285714285' >>> x = 10 * 3.25 >>> y = 200 * 200 >>> s = 'The value of x is ' + repr(x) + ', and y is ' + repr(y) + '...' diff --git a/Doc/tutorial/stdlib2.rst b/Doc/tutorial/stdlib2.rst index 0197a6f..4ae85b1 100644 --- a/Doc/tutorial/stdlib2.rst +++ b/Doc/tutorial/stdlib2.rst @@ -362,10 +362,13 @@ results in decimal floating point and binary floating point. The difference becomes significant if the results are rounded to the nearest cent:: >>> from decimal import * - >>> Decimal('0.70') * Decimal('1.05') + >>> x = Decimal('0.70') * Decimal('1.05') + >>> x Decimal('0.7350') - >>> .70 * 1.05 - 0.73499999999999999 + >>> x.quantize(Decimal('0.01')) # round to nearest cent + Decimal('0.74') + >>> round(.70 * 1.05, 2) # same calculation with floats + 0.73 The :class:`Decimal` result keeps a trailing zero, automatically inferring four place significance from multiplicands with two place significance. Decimal |