58 lines
No EOL
1.1 KiB
Python
58 lines
No EOL
1.1 KiB
Python
# Runestone.Academy thinkcspy course
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# Chapter 16
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# Problem 7
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import turtle
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def createLSystem(numIters, axiom):
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if numIters == 0:
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return axiom
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else:
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return createLSystem(numIters - 1, processString(axiom))
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def processString(oldStr):
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newstr = ""
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for ch in oldStr:
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newstr = newstr + applyRules(ch)
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return newstr
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def applyRules(ch):
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newstr = ""
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if ch == 'A':
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newstr = '-BF+AFA+FB-' # Rule 1
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elif ch == 'B':
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newstr = '+AF-BFB-FA+'
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else:
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newstr = ch # no rules apply so keep the character
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return newstr
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def drawLsystem(aTurtle, instructions, angle, distance):
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for cmd in instructions:
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if cmd == 'F':
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aTurtle.forward(distance)
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elif cmd == '+':
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aTurtle.left(angle)
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elif cmd == '-':
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aTurtle.right(angle)
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def main():
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inst = createLSystem(4, "A")
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t = turtle.Turtle()
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wn = turtle.Screen()
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t.up()
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t.back(200)
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t.down()
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t.speed(9)
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drawLsystem(t, inst, 90, 5)
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wn.exitonclick()
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main() |