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authorGeorg Brandl <georg@python.org>2009-08-13 08:47:18 (GMT)
committerGeorg Brandl <georg@python.org>2009-08-13 08:47:18 (GMT)
commit7d1e88063c6241d4750326fc772d5b8a6819a77f (patch)
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parent98e472d7fb88e8cf7c7797a879eb63cf3242ed97 (diff)
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Merged revisions 73656,73658,73663,73666 via svnmerge from
svn+ssh://svn.python.org/python/branches/py3k ........ r73656 | mark.dickinson | 2009-06-29 00:08:40 +0200 (Mo, 29 Jun 2009) | 1 line Fix description of range_length_obj ........ r73658 | raymond.hettinger | 2009-06-29 00:30:13 +0200 (Mo, 29 Jun 2009) | 1 line Small doc fix-ups to floatingpoint.rst. More are forthcoming. ........ r73663 | raymond.hettinger | 2009-06-29 01:21:38 +0200 (Mo, 29 Jun 2009) | 1 line Clean-up floating point tutorial. ........ r73666 | alexandre.vassalotti | 2009-06-29 03:13:41 +0200 (Mo, 29 Jun 2009) | 2 lines Make b64encode raises properly a TypeError when altchars is not bytes. ........
Diffstat (limited to 'Doc/tutorial')
-rw-r--r--Doc/tutorial/floatingpoint.rst10
1 files changed, 5 insertions, 5 deletions
diff --git a/Doc/tutorial/floatingpoint.rst b/Doc/tutorial/floatingpoint.rst
index e877a99..0230183 100644
--- a/Doc/tutorial/floatingpoint.rst
+++ b/Doc/tutorial/floatingpoint.rst
@@ -82,7 +82,7 @@ values share the same approximation, any one of them could be displayed
while still preserving the invariant ``eval(repr(x)) == x``.
Historically, the Python prompt and built-in :func:`repr` function would chose
-the one with 17 significant digits, ``0.10000000000000001``, Starting with
+the one with 17 significant digits, ``0.10000000000000001``. Starting with
Python 3.1, Python (on most systems) is now able to choose the shortest of
these and simply display ``0.1``.
@@ -123,9 +123,9 @@ Also, since the 0.1 cannot get any closer to the exact value of 1/10 and
Though the numbers cannot be made closer to their intended exact values,
the :func:`round` function can be useful for post-rounding so that results
-have inexact values that are comparable to one another::
+with inexact values become comparable to one another::
- >>> round(.1 + .1 + .1, 1) == round(.3, 1)
+ >>> round(.1 + .1 + .1, 10) == round(.3, 10)
True
Binary floating-point arithmetic holds many surprises like this. The problem
@@ -137,7 +137,7 @@ As that says near the end, "there are no easy answers." Still, don't be unduly
wary of floating-point! The errors in Python float operations are inherited
from the floating-point hardware, and on most machines are on the order of no
more than 1 part in 2\*\*53 per operation. That's more than adequate for most
-tasks, but you do need to keep in mind that it's not decimal arithmetic, and
+tasks, but you do need to keep in mind that it's not decimal arithmetic and
that every float operation can suffer a new rounding error.
While pathological cases do exist, for most casual use of floating-point
@@ -165,7 +165,7 @@ fraction::
>>> x = 3.14159
>>> x.as_integer_ratio()
- (3537115888337719L, 1125899906842624L)
+ (3537115888337719, 1125899906842624)
Since the ratio is exact, it can be used to losslessly recreate the
original value::