[Numpy-discussion] Questions about converting to numpy

Robert Kern robert.kern@gmail....
Wed Apr 25 16:31:50 CDT 2007


Christopher Barker wrote:

> I can only help with one:
>> - Even after reading the book I'm not really clear on why one would use 
>> numpy.float_ instead of numpy.float or float
> 
> They float and numpy.float are the same, and numpy.float_ is the same as 
> numpy.float64:
> 
>  >>> import numpy
>  >>> float is numpy.float
> True
>  >>> numpy.float64 is numpy.float64
> True
>  >>>
> 
> float was added to the numpy namespace so that we could write consistent 
> code like:
> 
> a = array(object, numpy.float32)
> b = array(object, numpy.float)
> 
> i.e. have it all in the same namespace.
> 
> I'm not sure why float_ is an alias for float64, though I'm guessing 
> it's possible that on some platforms they are not the same.

Rather, numpy.float used to be an alias for numpy.float64; however, it overrode
the builtin float() when "from numpy import *" was used at the interactive
prompt. Consequently, we renamed it numpy.float_ and specifically imported the
builtin float as numpy.float such that we didn't break code that had already
started using "numpy.float".

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco


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