[Numpy-discussion] changed behavior of numpy.histogram
Mark.Miller
mpmusu@cc.usu....
Wed Jan 23 11:07:18 CST 2008
Greetings: I just noticed a changed behavior of numpy.histogram. I
think that a recent 'fix' to the code has changed my ability to use that
function (albeit in an unconventional manner). I previously used the
histogram function to obtain counts of each unique string within a
string array. Again, I recognize that it is not a typical use of the
histogram function, but it did work very nicely for me.
Here's an example:
###numpy 1.0.3 --works just fine
>>> import numpy
>>> numpy.__version__
'1.0.3'
>>> a=numpy.array(('atcg', 'atcg', 'aaaa', 'aaaa'))
>>> a
array(['atcg', 'atcg', 'aaaa', 'aaaa'],
dtype='|S4')
>>> b=numpy.unique(a)
>>> numpy.histogram(a,b)
(array([2, 2]), array(['aaaa', 'atcg'],
dtype='|S4'))
>>>
###numpy 1.0.4 --no longer functions
>>> import numpy
>>> numpy.__version__
'1.0.4'
>>> a=numpy.array(('atcg', 'atcg', 'aaaa', 'aaaa'))
>>> a
array(['atcg', 'atcg', 'aaaa', 'aaaa'],
dtype='|S4')
>>> b=numpy.unique(a)
>>> numpy.histogram(a,b)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File
"/opt/libraries/python/python-2.5.1/numpy-1.0.4-gnu/lib/python2.5/site-packages/numpy/lib/function_base.py",
line 154, in histogram
if(any(bins[1:]-bins[:-1] < 0)):
TypeError: unsupported operand type(s) for -: 'numpy.ndarray' and
'numpy.ndarray'
>>>
Is this something that can possibly be fixed (should I submit a ticket)?
Or should I revert to some other approaches for implementing the same
idea? It really was a nice convenience. Or, alternately, would some
sort of new function along the lines of a numpy.countunique() ultimately
be useful?
Thanks,
-Mark
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