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1. WeatherGod commented on Jun 27, 2013

   

   WeatherGod

   on Jun 27, 2013

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   Perhaps you would be interested in MaskedArrays? Take a peek at
   np.ma.masked_invalid().

   Cheers!
   Ben Root
   On Jun 27, 2013 8:29 AM, "mmokrejs" notifications@github.com wrote:

   I was annoyed by numpy giving me sometimes this weird message. It turned
   out to be related to average() while not to median(). I see a pull #961https://github.com/matplotlib/matplotlib/issues/961but containing same warning messages in comment from 'jdh2358'.

   Anyway, here is my testcase:

   $ python
   Python 2.7.3 (default, Apr 20 2013, 18:28:22)
   [GCC 4.6.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.

   import numpy as np
   np.average([])
   /usr/lib64/python2.7/site-packages/numpy/core/_methods.py:57:
   RuntimeWarning: invalid value encountered in double_scalars
   ret = ret / float(rcount)
   nan
   np.median([])
   nan

   Sure, sometimes upstream code passes an empty list but I believe that is
   perfectly valid requirement. Please make your code more defensive. ;-)

   Personally am not happy at all with those NaN values but if you insist,
   return NaN in case of average() like you already do for median(). I zap
   them myself with None.

   A more general note on why I don't like NaN and how I got into the issue:

   def fix_clean_lists(indexes, func, _in, _out):
   """Overwrite NaN values (numpy.float64) with None or keep the float for
   average or round the float to integer for medians.
   """

   if _in:
   if func == 'median':
   for _indexpos in indexes:
   if _in[_indexpos]:
   _v = np.median(_in[_indexpos])
   try:
   _rounded = int(_v)
   except ValueError:
   # get rid rid of NaN which is a numpy.float64
   _out[_indexpos] = None
   else:
   _out[_indexpos] = _rounded
   elif func == 'average':
   for _indexpos in indexes:
   if _in[_indexpos]:
   # needed to get rid of:
   # fix_clean_lists() entered here for func average for [[], [], [], [], []]
   # /usr/lib64/python2.7/site-packages/numpy/core/_methods.py:57: RuntimeWarning: invalid value encountered in double_scalars
   # ret = ret / float(rcount)

               _v = np.average(_in[_indexpos])
               try:
                   _avg = int(_v)
               except ValueError:
                   # get rid rid of NaN which is a numpy.float64
                   _out[_indexpos] = None
               else:
                   _out[_indexpos] = round(_v, 2)
   

   —
   Reply to this email directly or view it on GitHubhttps://github.com//issues/2157
   .
2. tacaswell commented on Aug 17, 2014

   

   tacaswell

   on Aug 17, 2014

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   Closing as this should have been reported to numpy, not to mpl.
3. tacaswell

   closed this as completedon Aug 17, 2014