61 lines
No EOL
1.3 KiB
Python
61 lines
No EOL
1.3 KiB
Python
# Runestone.Academy thinkcspy course
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# Chapter 9
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# Problem 14
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# Your code here
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import turtle
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def createLSystem(numIters,axiom):
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startString = axiom
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endString = ""
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for i in range(numIters):
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endString = processString(startString)
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startString = endString
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return endString
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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 == 'X':
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newstr = 'X+YF+' # Rule 1
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elif ch == 'Y':
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newstr = '-FX-Y' # Rule 2
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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 == 'B':
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aTurtle.backward(distance)
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elif cmd == '+':
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aTurtle.right(angle)
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elif cmd == '-':
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aTurtle.left(angle)
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def main():
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inst = createLSystem(10, "FX") # create the string
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print(inst)
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t = turtle.Turtle() # create the turtle
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wn = turtle.Screen()
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wn.tracer(10)
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t.up()
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t.back(100)
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t.down()
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t.speed(0)
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drawLsystem(t, inst, 90, 5) # draw the picture
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# angle 90, segment length 5
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wn.exitonclick()
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main() |