| msg60684 - (view) |
Author: Stephen Thorne (jerub) * |
Date: 2005-02-28 05:10 |
| We have experienced a problem recently when wanting to render a large float as a string. Converting the float to an int/long manuall was required. '%d' % f throws an exception for all floats f, f >= 2**31 Expected output, shown with 'int()' and 'long()': >>> '%d %d' % (long(float(2**31)), int(float(2**31))) '2147483648 2147483648' Non-Working Example. >>> '%d' % float(2**31) Traceback (most recent call last): File "", line 1, in ? TypeError: int argument required Tested on: Python 2.3.4 (#1, Oct 26 2004, 16:42:40) Python 2.4.1a0 (#2, Feb 9 2005, 22:42:24) |
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| msg60685 - (view) |
Author: Josiah Carlson (josiahcarlson) *  |
Date: 2005-03-01 06:36 |
| Logged In: YES user_id=341410 Note that it will also raise a TypeError when the float f, f < -2**31 Is this a bug? I don't know. I tend to not pass floats when string interpolation is expecting integers. Maybe the documentation should be cleared up. If you really want a truncated float, perhaps "%.0f" is the format you are looking for, to save you the effort of using int() or long(). |
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| msg60686 - (view) |
Author: Stephen Thorne (jerub) * |
Date: 2005-03-01 13:21 |
| Logged In: YES user_id=100823 My immediate reaction is, yes. This is a bug. Either floats should work with %d, or they should not at all. Having a platform dependant upper bound on the size of the float allowed is a bug. |
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| msg60687 - (view) |
Author: Skip Montanaro (skip.montanaro) * |
Date: 2005-03-01 15:38 |
| Logged In: YES user_id=44345 This is probably a corner case that got missed in the int/long convergence. Still, is there a reason not to use %.f when you know you are passing a float and want to display it with no fractional component? >>> '%.f' % 2**50 '1125899906842624' or %ld if you expect the range to exceed the integer limits of your hardware? >>> '%ld' % 2**50 '1125899906842624' I agree the documentation could probably be improved in this area. |
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| msg60688 - (view) |
Author: Stephen Thorne (jerub) * |
Date: 2005-03-01 23:53 |
| Logged In: YES user_id=100823 %ld doesn't help. see the following example: >>> "%.f" % float(2**31) '2147483648' >>> "%ld" % float(2**31) Traceback (most recent call last): File "", line 1, in ? TypeError: int argument required |
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| msg60689 - (view) |
Author: Skip Montanaro (skip.montanaro) * |
Date: 2005-03-02 00:42 |
| Logged In: YES user_id=44345 Sorry, I got corn-fused and misinterpreted 2**50 as 2e50. |
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| msg60690 - (view) |
Author: Armin Rigo (arigo) *  |
Date: 2005-03-17 12:21 |
| Logged In: YES user_id=4771 I am afraid that the same problem occurs all over the place, wherever long integers are accepted by built-in operations or functions. Most of these places accept (and round) a float argument as well, though this is supposedly deprecated. For example: f = open('filename') f.seek(999999999999) # ok f.seek(12.0) # ok f.seek(999999999999.0) # OverflowError Unless someone is willing to conduct a systematic review I believe it unlikely that it will get fixed, given the deprecation status. |
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| msg61406 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2008-01-21 16:39 |
| This is a duplicate of issue #1742669 |
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