[Tutor] Need to write a python and call it within a python main program (fwd)

[Kermit Rose]

From: Danny Yoo
Date: 02/18/06 15:18:14
To: Kermit Rose
Cc: Tutor
Subject: Re: [Tutor] Need to write a python and call it within a python main
program (fwd)
 
  
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 *********

ok

***************
> ***************
 
 
Python has a familiar control-flow syntax for branches in the 'if'
statement.  For example, here is an interactive session that shows how one
can use it for a simple case-analysis:
 
######
>>> def is_even(n):
....     if n % 2 == 0:        ## % is the modulo operator
....         return "yes"
....     else:
....         return "no"
....
>>> is_even(42)
'yes'
>>> is_even(13)
'no'
######


******

This is a very good example.


Using it,  I translate my pseudo code

set j = 8 * mod(a,2) + 4 * mod(b,2) + 2 * mod(c,2) + mod(d,2)

if j = 0,  a,b,c,d = a/2,b/2,c/2,d/2
if j = 1,  a,b,c,d = -1,-1,-1,-1
if j = 2,  a,b,c,d = a,b/2,c,d/2
if j = 3,  a,b,c,d = a,(a+b)/2,c,(d-c)/2
if j = 4,  a,b,c,d = a,b,c/2,d/2
if j = 5,  a,b,c,d = a,b,(a+c)/2,(d-b)/2
if j = 6,  a,b,c,d = b,a,d,c
if j = 7,  a,b,c,d = b,a,d,c
if j = 8,  a,b,c,d = -1,-1,-1,-1
if j = 9,  a,b,c,d = 2*a,a+b,a+c,(d-a-b-c)/2
if j = 10, a,b,c,d = b,a,d,c
if j = 11, a,b,c,d = 2*a,a+b,c,(d-c)/2
if j = 12, a,b,c,d = b,a,d,c
if j = 13, a,b,c,d = 2*a,b,a+c,(d-b)/2
if j = 14, a,b,c,d = b,a,d,c
if j = 15, a,b,c,d = a,a+b,a+c,d-a-b-c


into


>>> def trans01(a,b,c,d):
....     j = 8 * a%2 + 4 * b%2 + 2 * c%2 + d%2
....    if j = 0,  a,b,c,d = a/2,b/2,c/2,d/2
....   if j = 1,  a,b,c,d = -1,-1,-1,-1
....   if j = 2,  a,b,c,d = a,b/2,c,d/2
....   if j = 3,  a,b,c,d = a,(a+b)/2,c,(d-c)/2
....   if j = 4,  a,b,c,d = a,b,c/2,d/2
....   if j = 5,  a,b,c,d = a,b,(a+c)/2,(d-b)/2
....   if j = 6,  a,b,c,d = b,a,d,c
....   if j = 7,  a,b,c,d = b,a,d,c
....   if j = 8,  a,b,c,d = -1,-1,-1,-1
....   if j = 9,  a,b,c,d = 2*a,a+b,a+c,(d-a-b-c)/2
....   if j = 10, a,b,c,d = b,a,d,c
....   if j = 11, a,b,c,d = 2*a,a+b,c,(d-c)/2
....   if j = 12, a,b,c,d = b,a,d,c
....   if j = 13, a,b,c,d = 2*a,b,a+c,(d-b)/2
....   if j = 14, a,b,c,d = b,a,d,c
....   if j = 15, a,b,c,d = a,a+b,a+c,d-a-b-c
IndentationError: expected an indented block (<pyshell#0>, line 2)
>>> 
>>> 
>>> 



Why did I get this error message? 



Kermit   <   kermit at polaris.net   >








 
 
 
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