[Numpy-discussion] Numpy set_printoptions, silent failure, bug?

[John Ladasky]

Hi there,

I've been using Numpy for several years and appreciate it very much.

The following minimal code has been tried on Python 3.4 and 3.5, with Numpy
1.8 and Numpy 1.11, respectively. I want to temporarily change the way
that a Numpy array is printed, then change it back.

import numpy as np

a = np.random.random((4,3))
print(a, "\n")
opt = np.get_printoptions()
np.set_printoptions(precision = 3, suppress = True)
print(a, "\n")
np.set_printoptions(opt)
print(a, "\n\nDone.\n")


Here is the traceback:


Traceback (most recent call last):
File "set_printoptions test.py", line 11, in <module>
print(a, "\n\nDone.\n")
File "/usr/lib/python3/dist-packages/numpy/core/numeric.py", line 1615,
in array_str
return array2string(a, max_line_width, precision, suppress_small, ' ',
"", str)
File "/usr/lib/python3/dist-packages/numpy/core/arrayprint.py", line 454,
in array2string
separator, prefix, formatter=formatter)
File "/usr/lib/python3/dist-packages/numpy/core/arrayprint.py", line 328,
in _array2string
_summaryEdgeItems, summary_insert)[:-1]
File "/usr/lib/python3/dist-packages/numpy/core/arrayprint.py", line 523,
in _formatArray
summary_insert)
File "/usr/lib/python3/dist-packages/numpy/core/arrayprint.py", line 497,
in _formatArray
word = format_function(a[-i]) + separator
File "/usr/lib/python3/dist-packages/numpy/core/arrayprint.py", line 616,
in __call__
s = self.format % x
AttributeError: 'FloatFormat' object has no attribute 'format'


It took me a while to discover the bug, on the second to last line. That
line should read:

np.set_printoptions(**opt)


This unpacks the dictionary, opt, which was retrieved earlier in the
program with the call to get_printoptions.

I am wondering why set_printoptions would accept the dictionary as a single
argument. Shouldn't that raise a TypeError or something?

The AttributeError that is raised the next time that one attempts to print
a numpy array is remote from the problem, and thus rather uninformative,
which is why I did not immediately diagnose my error.

Should this be considered a Numpy bug, or is there some reason that
set_printoptions would legitimately need to accept a dictionary as a single
argument?

[Robert Kern]

Post by John Ladasky
Should this be considered a Numpy bug, or is there some reason that

set_printoptions would legitimately need to accept a dictionary as a single
argument?

There is no such reason. One could certainly add more validation to the
arguments to np.set_printoptions().

--
Robert Kern

[John Ladasky]

Hi Robert,

Thanks for your reply. If no one disagrees with you or with me that this
is a Numpy bug, I would appreciate being directed to the appropriate page
to submit a bug-fix request.

Post by John Ladasky

Post by John Ladasky
Should this be considered a Numpy bug, or is there some reason that

set_printoptions would legitimately need to accept a dictionary as a single
argument?
There is no such reason. One could certainly add more validation to the
arguments to np.set_printoptions().
--
Robert Kern
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NumPy-Discussion mailing list
https://mail.scipy.org/mailman/listinfo/numpy-discussion

[Juan Nunez-Iglesias]

https://github.com/numpy/numpy/issues


From: John Ladasky <***@itu.edu> <***@itu.edu>
Reply: Discussion of Numerical Python <numpy-***@scipy.org>
<numpy-***@scipy.org>
Date: 20 July 2016 at 7:49:10 AM
To: Discussion of Numerical Python <numpy-***@scipy.org>
<numpy-***@scipy.org>
Subject: Re: [Numpy-discussion] Numpy set_printoptions, silent failure,
bug?

Hi Robert,

Post by John Ladasky
Thanks for your reply. If no one disagrees with you or with me that this
is a Numpy bug, I would appreciate being directed to the appropriate page
to submit a bug-fix request.

Post by John Ladasky

Post by John Ladasky
Should this be considered a Numpy bug, or is there some reason that

set_printoptions would legitimately need to accept a dictionary as a single
argument?
There is no such reason. One could certainly add more validation to the
arguments to np.set_printoptions().
--
Robert Kern
_______________________________________________
NumPy-Discussion mailing list
https://mail.scipy.org/mailman/listinfo/numpy-discussion

--
*John J. Ladasky Jr., Ph.D.*
*Research Scientist*
*International Technological University*
*2711 N. First St, San Jose, CA 95134 USA*
_______________________________________________
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[John Ladasky]

Thank you Juan, I've just joined GitHub and I've submitted the description
of the bug.

Post by Juan Nunez-Iglesias
https://github.com/numpy/numpy/issues
Date: 20 July 2016 at 7:49:10 AM
Subject: Re: [Numpy-discussion] Numpy set_printoptions, silent failure,
bug?
Hi Robert,

Post by John Ladasky
Thanks for your reply. If no one disagrees with you or with me that this
is a Numpy bug, I would appreciate being directed to the appropriate page
to submit a bug-fix request.

Post by John Ladasky

Post by John Ladasky
Should this be considered a Numpy bug, or is there some reason that

set_printoptions would legitimately need to accept a dictionary as a single
argument?
There is no such reason. One could certainly add more validation to the
arguments to np.set_printoptions().
--
Robert Kern
_______________________________________________
NumPy-Discussion mailing list
https://mail.scipy.org/mailman/listinfo/numpy-discussion

--
*John J. Ladasky Jr., Ph.D.*
*Research Scientist*
*International Technological University*
*2711 N. First St, San Jose, CA 95134 USA*
_______________________________________________
NumPy-Discussion mailing list
https://mail.scipy.org/mailman/listinfo/numpy-discussion

_______________________________________________
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