Simon Brunning wrote:
On 23 Mar 2005 21:03:04 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Is there something out there like "Python for kids" which would explain
*basic* programming concepts in a way which is accessible and
entertaining for kids aged 10-14 (that about where her brain is right
now) and which would allow them to "play around" and have fun solving
small problems?
I don't know about kid's tutorials, but I can recommend that you try
the turtle module. It's great for kids. It gives really good immediate
feedback, You can start out using it interactively:
<snip>
Couldn't help myself. I had to write the Dragon Fractal in python.turtle
:)
"""Generates the L-System for the Dragon Fractal, using
the turtle module."""
import re, turtle
from math import sin, pi
"""The default L-System rules for the dragon fractal are:
Angle 45 degrees
Starting Axiom FX
F =
Y = +FX--FY+
X = -FX++FY-
I've optimised them a little bit the following ways:
Take out all occurances of F.
Replace Y with +FN--FY+
Replace X with -FX++FY-
Replace N with X
Take out all occurances of -+
Take out all occurances of +- """
def rules(instring):
"""I originally had this as a series of nested re.sub expressions.
Once the rule list got long though, I split it up to make it more
"pythonic". """
newstring, subs = re.subn("F", "", instring)
# Use N as a placeholder for X
newstring, subs = re.subn("Y", "+FN--FY+", newstring)
# So that we don't get double substitution.
newstring, subs = re.subn("X", "-FX++FY-", newstring)
# Now we replace the placeholder with X
newstring, subs = re.subn("N", "X", newstring)
# And optimise the string in regard to left/right turns.
subs = 1
while subs:
newstring, first = re.subn("-\+", "", newstring)
newstring, second = re.subn("\+-", "", newstring)
subs = first + second
return newstring
def colorator(value):
# Makes the colour of the cursor cycle.
range, fract = divmod(value*6, 1)
if range == 0:
red = 1.0
green = fract
blue = 0.0
elif range == 1:
red = 1.0 - fract
green = 1.0
blue = 0.0
elif range == 2:
red = 0.0
green = 1.0
blue = fract
elif range == 3:
red = 0.0
green = 1.0 - fract
blue = 1.0
elif range == 4:
red = fract
green = 0.0
blue = 1.0
elif range >= 5:
red = 1.0
green = 0.0
blue = 1.0 - fract
return red, green, blue
# The default is that the turtle will only move one pixel
def parser(parsestring, distance=1, angle=45):
# First we clean up the parsestring
newstring = re.sub("X", "", parsestring)
newstring = re.sub("Y", "", newstring)
# Clear the screen
turtle.clear()
strlen = len(newstring)
colorinc = 1.0 / float(strlen)
turtle.color(colorator(0))
for i in range(strlen):
value = newstring[i]
turtle.color(colorator(float(i) * colorinc))
if value == "+":
turtle.right(angle)
elif value == "-":
turtle.left(angle)
elif value == "F":
turtle.forward(distance)
# Hide the cursor
turtle.color(1.0,1.0,1.0)
def run(count=15, distance=1, angle=45, width=1):
string = "FX"
while count > 0:
string = rules(string)
count -= 1
# "Hide" the cursor while we are moving it.
## print string
turtle.width(width)
turtle.color(1.0,1.0,1.0)
# Move the cursor so the turtle won't go off the screen.
# You might want to resize the turtle screen while the program is doing this
turtle.setx(100)
turtle.sety(-200)
parser(string, distance=distance, angle=angle)
if __name__ == "__main__":
run(15)
--
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