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Diffstat (limited to 'Doc/tutorial/floatingpoint.rst')
| -rw-r--r-- | Doc/tutorial/floatingpoint.rst | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/Doc/tutorial/floatingpoint.rst b/Doc/tutorial/floatingpoint.rst index c06568e..863fb28 100644 --- a/Doc/tutorial/floatingpoint.rst +++ b/Doc/tutorial/floatingpoint.rst @@ -92,18 +92,17 @@ thing in all languages that support your hardware's floating-point arithmetic (although some languages may not *display* the difference by default, or in all output modes). -Python's built-in :func:`str` function produces only 12 significant digits, and -you may wish to use that instead. It's unusual for ``eval(str(x))`` to -reproduce *x*, but the output may be more pleasant to look at:: +For more pleasant output, you may may wish to use string formatting to produce a limited number of significant digits:: - >>> str(math.pi) + >>> format(math.pi, '.12g') # give 12 significant digits '3.14159265359' + >>> format(math.pi, '.2f') # give 2 digits after the point + '3.14' + >>> repr(math.pi) '3.141592653589793' - >>> format(math.pi, '.2f') - '3.14' It's important to realize that this is, in a real sense, an illusion: you're simply rounding the *display* of the true machine value. |