9b5e00fcc5
Formerly, py/formatfloat would print whole numbers inaccurately with nonzero digits beyond the decimal place. This resulted from its strategy of successive scaling of the argument by 0.1 which cannot be exactly represented in floating point. The change in this commit avoids scaling until the value is smaller than 1, so all whole numbers print with zero fractional part. Fixes issue #4212. Signed-off-by: Dan Ellis dan.ellis@gmail.com
16 lines
540 B
Python
16 lines
540 B
Python
# Test formatting of very large ints.
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# Relies on double-precision floats.
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import array
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import sys
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# Challenging way to express 1e200 and 1e100.
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print("{:.12e}".format(float("9" * 400 + "e-200")))
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print("{:.12e}".format(float("9" * 400 + "e-300")))
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# These correspond to the binary representation of 1e200 in float64s:
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v1 = 0x54B249AD2594C37D # 1e100
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v2 = 0x6974E718D7D7625A # 1e200
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print("{:.12e}".format(array.array("d", v1.to_bytes(8, sys.byteorder))[0]))
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print("{:.12e}".format(array.array("d", v2.to_bytes(8, sys.byteorder))[0]))
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