[Tutor] scaling values

[David Heiser]

Is this what you're asking for?


# Scaler.py
#

def scale(OldList, NewMin, NewMax):
    NewRange = float(NewMax - NewMin)
    OldMin = min(x)
    OldMax = max(x)
    OldRange = float(OldMax - OldMin)
    ScaleFactor = NewRange / OldRange
    print '\nEquasion:  NewValue = ((OldValue - ' + str(OldMin) + ') x '
+ str(ScaleFactor) + ') + ' + str(NewMin) + '\n'
    NewList = []
    for OldValue in OldList:
        NewValue = ((OldValue - OldMin) * ScaleFactor) + NewMin
        NewList.append(NewValue)
    return NewList

x = [13, 71, 120, 88, 82, 100, 10, 65, 101, 45, 26]
foo = scale(x, 0, 1.0)

##x = [.12789, .982779, .19798198, .266796, .656527, .257877091]
##foo = scale(x, 0, 127)

##x = [0, 50, 100]
##foo = scale(x, 32, 212)

##x = [32, 122, 212]
##foo = scale(x, 0, 100)

print 'New List = ' + str(foo)
Print


>>> 

Equasion:  NewValue = ((OldValue - 10) x 0.00909090909091) + 0

New List = [0.027272727272727271, 0.55454545454545456, 1.0,
0.70909090909090911, 0.65454545454545454, 0.81818181818181812, 0.0, 0.5,
0.82727272727272727, 0.31818181818181818, 0.14545454545454545]

>>> 



-----Original Message-----
From: tutor-bounces at python.org [mailto:tutor-bounces at python.org] On
Behalf Of kevin parks
Sent: Tuesday, March 14, 2006 1:03 AM
To: tutor at python.org
Subject: [Tutor] scaling values


i have various functions (that i didn't write) that put out data in 
lists of various types. But some functions (which i didn't write) that 
expect the data to be scaled, sometimes 0-1 sometimes 1-2, sometimes 
0-127..., sometimes 0 - 32768... gosh you name it. In other words i 
have a bunch of black boxes that don't speak the same language .... is 
there a scaling function in python (or numeric or scipy) that can scale 
a list of values to a high precision?

x = [13, 71, 120, 88, 82, 100, 10, 65, 101, 45, 26]

foo = scale(x, 0, 1.0)

and get that list scaled 0 to 1, or if i had:

x = [.12789, .982779, .19798198, .266796, .656527, .257877091]

foo = scale(x, 0, 127)

cheers,

-kp--

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