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List:       python-list
Subject:    Re: Optimizing if statement  check over a numpy value
From:       Jeremy Sanders <jeremy () jeremysanders ! net>
Date:       2015-07-23 11:42:31
Message-ID: moqjuo$3nq$1 () ger ! gmane ! org
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Heli Nix wrote:

> Is there any way that I can optimize this if statement.

Array processing is much faster in numpy. Maybe this is close to what you 
want

import numpy as N
# input data
vals = N.array([42, 1, 5, 3.14, 53, 1, 12, 11, 1])
# list of items to exclude
exclude = [1]
# convert to a boolean array
exclbool = N.zeros(vals.shape, dtype=bool)
exclbool[exclude] = True
# do replacement
ones = vals==1.0
# Note: ~ is numpy.logical_not
vals[ones & (~exclbool)] = 1e-20

I think you'll have to convert your HDF array into a numpy array first, 
using numpy.array().

Jeremy


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