[Numpy-discussion] long integers in loadtxt -- bad parsing?

Andrew Jaffe a.h.jaffe@gmail....
Thu Apr 8 09:42:02 CDT 2010


Hi all,

I am trying to read some 19-digit integers using loadtxt (or genfromtxt 
-- same problem). The numbers are smaller than the max int64 (and the 
max uint64 -- same problem with either one).

Below, Out[184] shows that python has no problem with the conversion, 
but loadtxt gets the last few digits wrong in Out[185].

Am I doing something stupid?

Yours,

Andrew



In [175]: import numpy as np

In [176]: np.__version__
Out[176]: '1.4.0'

In [177]: from StringIO import StringIO

In [178]: fc = """1621174818000457763
1621209600996363377
1621258907994644735
1621296000994995765
1621374194996298305
"""

In [184]: long(fc[:19])
Out[184]: 1621174818000457763L

In [185]: np.loadtxt(StringIO(fc), dtype=np.int64)
Out[185]:
array([1621174818000457728, 1621209600996363264, 1621258907994644736,
        1621296000994995712, 1621374194996298240], dtype=int64)







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