Object Not Callable, float?

[W. eWatson]

Ben Finney wrote:
> "W. eWatson" <wolftracks at invalid.com> writes:
> 
>> "C:\Sandia_Meteors\Sentinel_Development\Development_Sentuser+Utilities\sentuser\sentuser_20090103+hist.py",
>> line 467, in ShowHistogram
>>     mean = sum(hist)
>> TypeError: 'float' object is not callable
> 
> It means you're calling an object of type ‘float’. The line where it
> occurred shows that you're accessing that object through the name ‘sum’,
> which means you've bound the name ‘sum’ to a float object.
> 
>> for the code:
>> ----------------------
>>         sum = 0.0
> 
> Here you clobber the existing binding of ‘sum’, binding it to the float
> value 0.0.
> 
>>         avg = 0.0
>>         nplt_bins = 32
>>         for i in range(len(hist)):
>> #             msg = "%5d %6d\n" % (i,hist[i])
>>             msg = "%5d %6d\n" % (i,hist[i])
>>             sum = sum + hist[i]
> 
> Here you keep re-binding the name ‘sum’ to new float objects of
> different value.
> 
>>             text.insert( END, msg )
>>         for i in range(len(hist)):
>>             avg = avg + (i*hist[i]/sum)
>>
>>         mean = sum(hist)   <-------------- faulty line
> 
> Here you try to call the object referenced by the name ‘sum’, which is a
> float object.
> 
>> hist is a list of 256 integers. What does float have to do with this?
> 
> You explicitly bound the name ‘sum’ to an object of type ‘float’.
> 
> Solution: Choose names wisely, and if you want to use a built-in name
> like ‘sum’ for its built-in putpose, don't clobber that binding before
> using it.
> 
Yikes. Thanks very much. Python seems to act unlike other language in 
which words like float are reserved. I'll use asum.