numpy.where behavior

Robert Kern robert.kern at
Mon Nov 13 22:16:55 CST 2006

Tim Hochberg wrote:
> Another little tidbit: this is not as general as where, and could 
> probably be considered a little too clever to be clear, but:
>         b = 1 / (a + (a==0.0))
> is faster than using where in this particular case and sidesteps the 
> divide by zero issue altogether.

A less clever approach that does much the same thing:

  b = 1.0 / where(a==0, 1.0, a)

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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