issue19075: add visual sorting algorithms to turtledemo; original code from Jason Yeo
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@ -2351,6 +2351,9 @@ The demo scripts are:
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| | pairwise in opposite | shapesize, tilt, |
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| | direction | get_shapepoly, update |
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+----------------+------------------------------+-----------------------+
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| sorting_animate| visual demonstration of | simple alignment, |
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| | different sorting methods | randomization |
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+----------------+------------------------------+-----------------------+
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| tree | a (graphical) breadth | :func:`clone` |
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| | first tree (using generators)| |
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+----------------+------------------------------+-----------------------+
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@ -0,0 +1,204 @@
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#!/usr/bin/env python3
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"""
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sorting_animation.py
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A minimal sorting algorithm animation:
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Sorts a shelf of 10 blocks using insertion
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sort, selection sort and quicksort.
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Shelfs are implemented using builtin lists.
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Blocks are turtles with shape "square", but
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stretched to rectangles by shapesize()
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---------------------------------------
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To exit press space button
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---------------------------------------
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"""
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from turtle import *
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import random
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class Block(Turtle):
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def __init__(self, size):
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self.size = size
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Turtle.__init__(self, shape="square", visible=False)
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self.pu()
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self.shapesize(size * 1.5, 1.5, 2) # square-->rectangle
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self.fillcolor("black")
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self.st()
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def glow(self):
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self.fillcolor("red")
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def unglow(self):
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self.fillcolor("black")
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def __repr__(self):
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return "Block size: {0}".format(self.size)
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class Shelf(list):
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def __init__(self, y):
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"create a shelf. y is y-position of first block"
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self.y = y
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self.x = -150
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def push(self, d):
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width, _, _ = d.shapesize()
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# align blocks by the bottom edge
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y_offset = width / 2 * 20
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d.sety(self.y + y_offset)
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d.setx(self.x + 34 * len(self))
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self.append(d)
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def _close_gap_from_i(self, i):
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for b in self[i:]:
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xpos, _ = b.pos()
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b.setx(xpos - 34)
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def _open_gap_from_i(self, i):
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for b in self[i:]:
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xpos, _ = b.pos()
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b.setx(xpos + 34)
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def pop(self, key):
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b = list.pop(self, key)
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b.glow()
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b.sety(200)
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self._close_gap_from_i(key)
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return b
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def insert(self, key, b):
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self._open_gap_from_i(key)
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list.insert(self, key, b)
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b.setx(self.x + 34 * key)
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width, _, _ = b.shapesize()
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# align blocks by the bottom edge
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y_offset = width / 2 * 20
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b.sety(self.y + y_offset)
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b.unglow()
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def isort(shelf):
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length = len(shelf)
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for i in range(1, length):
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hole = i
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while hole > 0 and shelf[i].size < shelf[hole - 1].size:
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hole = hole - 1
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shelf.insert(hole, shelf.pop(i))
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return
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def ssort(shelf):
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length = len(shelf)
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for j in range(0, length - 1):
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imin = j
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for i in range(j + 1, length):
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if shelf[i].size < shelf[imin].size:
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imin = i
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if imin != j:
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shelf.insert(j, shelf.pop(imin))
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def partition(shelf, left, right, pivot_index):
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pivot = shelf[pivot_index]
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shelf.insert(right, shelf.pop(pivot_index))
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store_index = left
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for i in range(left, right): # range is non-inclusive of ending value
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if shelf[i].size < pivot.size:
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shelf.insert(store_index, shelf.pop(i))
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store_index = store_index + 1
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shelf.insert(store_index, shelf.pop(right)) # move pivot to correct position
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return store_index
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def qsort(shelf, left, right):
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if left < right:
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pivot_index = left
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pivot_new_index = partition(shelf, left, right, pivot_index)
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qsort(shelf, left, pivot_new_index - 1)
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qsort(shelf, pivot_new_index + 1, right)
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def randomize():
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disable_keys()
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clear()
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target = list(range(10))
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random.shuffle(target)
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for i, t in enumerate(target):
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for j in range(i, len(s)):
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if s[j].size == t + 1:
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s.insert(i, s.pop(j))
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show_text(instructions1)
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show_text(instructions2, line=1)
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enable_keys()
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def show_text(text, line=0):
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line = 20 * line
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goto(0,-250 - line)
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write(text, align="center", font=("Courier", 16, "bold"))
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def start_ssort():
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disable_keys()
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clear()
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show_text("Selection Sort")
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ssort(s)
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clear()
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show_text(instructions1)
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show_text(instructions2, line=1)
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enable_keys()
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def start_isort():
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disable_keys()
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clear()
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show_text("Insertion Sort")
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isort(s)
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clear()
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show_text(instructions1)
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show_text(instructions2, line=1)
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enable_keys()
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def start_qsort():
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disable_keys()
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clear()
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show_text("Quicksort")
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qsort(s, 0, len(s) - 1)
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clear()
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show_text(instructions1)
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show_text(instructions2, line=1)
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enable_keys()
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def init_shelf():
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global s
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s = Shelf(-200)
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vals = (4, 2, 8, 9, 1, 5, 10, 3, 7, 6)
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for i in vals:
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s.push(Block(i))
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def disable_keys():
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onkey(None, "s")
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onkey(None, "i")
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onkey(None, "q")
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onkey(None, "r")
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def enable_keys():
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onkey(start_isort, "i")
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onkey(start_ssort, "s")
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onkey(start_qsort, "q")
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onkey(randomize, "r")
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onkey(bye, "space")
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def main():
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getscreen().clearscreen()
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ht(); penup()
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init_shelf()
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show_text(instructions1)
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show_text(instructions2, line=1)
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enable_keys()
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listen()
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return "EVENTLOOP"
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instructions1 = "press i for insertion sort, s for selection sort, q for quicksort"
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instructions2 = "spacebar to quit, r to randomize"
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if __name__=="__main__":
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msg = main()
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mainloop()
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