[Tutor] Anyone fancy giving me some tips and an expert opinion??

[Ricardo Aráoz]

Damian Archer wrote:
> I have written what i see as a pretty decent script to resolve this
> question:
> 
> Write an improved version of the Chaos program from Chapter 1 that
> allows a user to input two initial
> values and the number of iterations and then prints a nicely formatted
> table showing how the values
> change over time. For example, if the starting values were .25 and .26
> with 10 iterations, the table
> might look like this:
> index 0.25 0.26
> ----------------------------
> 1 0.731250 0.750360
> 2 0.766441 0.730547
> 3 0.698135 0.767707
> 4 0.821896 0.695499
> 5 0.570894 0.825942
> 6 0.955399 0.560671
> 7 0.166187 0.960644
> 8 0.540418 0.147447
> 9 0.968629 0.490255
> 10 0.118509 0.974630
> 
> Although it works I am sure I could have gone about this a better way,
> it probably doesn't fit all the rules of best practice either. Was
> wondering if anyone would mind having a look and offering a few tips??
> 
> # chaos.py
> # A program to mimic the chaos theory
> 
> def main():
> 
>     print "Example of Chaos"
> 
>     # User inputs numbers to compare, z is for the index counter
>     x = input("Enter a number between 1 and 0: ")
>     y = input("Enter a second number between 1 and 0: ")
>     z = 0
> 
>     # Prints the table borders and titles
>     print '%10s %20s %20s' % ("Index", x, y)
>     print "-----------------------------
> -----------------------------"
>     tempx = x
>     tempy = y
> 
>     # Loops calculates 'chaotic behaviour for input numbers
>     for i in range(10):
>         tempx = 3.9 * tempx * (1 - tempx)
>         tempy = 3.9 * tempy * (1 - tempy)
>         z = z + 1
>         # Print chaotice results into table
>         print '%10s %20s %20s' % (z, tempx, tempy)
> 
>     raw_input("Press any key to exit")
>     
> main()
> 


>From a procedural POV,
UNTESTED :


# chaos.py
# A program to mimic the chaos theory

def main() :
    print "Example of Chaos"
    x, y, iterations = getUserInput()
    printTitles(x, y)
    for i in range(1, iterations+1)
        print '%10s %20s %20s' % (i, chaos(x), chaos(y))
    raw_input("Press any key to exit")

def printTitles(x, y) :
    # Prints the table borders and titles
    print '%10s %20s %20s' % ("Index", x, y)
    print "----------------------------------------------------------"

def getUserInput() :
    # Should put this inside a try/except block
    x = float(raw_input("Enter a number between 1 and 0: "))
    y = float(raw_input("Enter a second number between 1 and 0: "))
    iterations = float(raw_input("Enter a number of iterations: "))

    return x, y, iterations

def chaos(x) :
    return (3.9 * x * (1 - x))


if __name__ == '__main__' :
    main()