bob = Turtle()
bob.shape("turtle")
class SimpleDraw(Turtle):
def __init__(Turtle):
bob = Turtle
def draw_square(bob, length):
'''This function draws a regular square'''
for i in range(4):
bob.forward(length)
bob.left(90)
def draw_polygon(bob, n, length):
'''This function draws a regular polygon'''
angle = 360.0 / n
for i in range(n):
bob.forward(length)
bob.left(angle)
def draw_circle (t, r):
circumference = 2 * math.pi * r
n = 50
length = circumference / n
polygon (t, n, length)
drawObj = SimpleDraw
drawObj.draw_polygon
drawObj.draw_circle
drawObj.draw_square
def testSimpleDraw():
number = raw_input('Please choose a draw option: \
1-draw square \
2-draw polygon \
3-draw circle \
0-to exit');
if number == 0:
exit()
else:
if number == 1:
drawObj.draw_square(bob, 5)
else:
if number == 2:
drawObj.draw_polygon(bob, 7, 70)
else:
if number == 3:
drawObj.draw_circle(50, 50)
if __name__ == '__main__':
testSimpleDraw()
答案 0 :(得分：1)
drawObj = SimpleDraw需要更改为drawObj = SimpleDraw()
这就是你实例化一个类的方法。您正在将SimpleDraw类分配给drawObj - drawObj与SimpleDraw类相同，而不是代码中的SimpleDraw实例。
答案 1 :(得分：0)
在这一行：
drawObj = SimpleDraw
您将类 SimpleDraw分配给名称drawObj。相反，您应该创建要分配的类的实例：
drawObj = SimpleDraw() # note parentheses
您的__init__课程中不需要SimpleDraw;你从Turtle继承了这个。通常将第一个参数调用实例方法self，而不是bob！例如：
def draw_square(self, length):
'''This function draws a regular square'''
for i in range(4):
self.forward(length)
self.left(90)
您需要调整draw_circle方法才能正确调用draw_polygon方法：
def draw_circle(self, r, n=50):
circumference = 2 * math.pi * r
length = circumference / n
self.draw_polygon(n, length)
请注意，您可以使用elif来简化代码：
if number == 0:
...
elif number == 1:
...
答案 2 :(得分：0)
我要猜测你想要做什么。首先，让我们重写这段代码，然后我会解释这些变化。
class SimpleDraw(Turtle):
# No __init__ need, calls __init__ of subclass implicitly
# So self refers to an instance of Turtle
# Since all your code essentially makes use of the same thing, lets create
# a generic base draw.
def draw_generic(self, angle, length, n):
for i in range(n):
self.forward(length)
self.left(angle)
def draw_square(self, length):
# Notice self instead of bob, this is how you refer to the instance
# of the class that has been created.
"""
This function draws a regular square.
"""
self.draw_generic(90, length, 4) # Note, self implicitly passed
def draw_polygon(self, n, length):
"""
This function draws a regular polygon
"""
angle = 360.0 / n
self.draw_generic(angle, length, n)
def draw_circle(self, t, r):
circumference = 2 * math.pi * r
n = 50
length = circumference / n
self.draw_polygon(t, n, length) # Note: draw_polygon instead of polygon
def test_simple_draw():
# Note the lowercase and underscores, this preferred by PEP 8
# http://stackoverflow.com/questions/8908760/should-i-use-camel-case-or-underscores-in-python
options = ["1 - draw square", "2 - draw polygon", "3 - draw circle", "0 -exit"]
msg = "Please choose a draw option:\n %s" % ("\n".join(options))
# Note that number is a string, so we have to try and coerce it to an int, and
# validate this as well.
number = None
while number is None:
try:
number = raw_input(msg)
number = int(number)
if 0 > number or 3 < number:
raise ValueError # Not a valid option
except ValueError: # If the coercion fails
print "%s is not a valid option. Please re-enter." % number
number = None # Set to None so we loop again
# Now we have the number, and it's actually a number.
# You make a lot of use of else, which can be replaced by elif, which is the
# like else but specifies a condition; a union of if and else
drawObj = SimpleDraw() # We create our object here, note braces for instantiation
if number == 0:
exit()
elif number == 1:
drawObj.draw_square(5)
elif number == 2:
drawObj.draw_polygon(7, 70)
else: # We can have confidence in this value because of our checks above
drawObj.draw_circle(50, 50)
if __name__ == "__main__":
test_simple_draw()
现在，这段代码涵盖了您最初想要的想法，但是使用了您最初尝试使用的类继承。
进一步参考资料来源：
课程：http://docs.python.org/2/tutorial/classes.html
答案 3 :(得分：0)
import math
import random
import turtle
class SimpleTurtle(turtle.Turtle):
# There is no need to override the default __init__
# Also, making the self argument 'bob' is just irritating -
# everyone expects to see 'self', why mess us up?
def draw_polygon(self, num_sides, side_length):
"""
Draw an n-sided regular polygon
"""
angle = 360. / num_sides
for side in range(num_sides):
self.forward(side_length)
self.left(angle)
def draw_square(self, side_length):
"""
Draw a square
"""
self.draw_polygon(4, side_length)
def draw_circle(self, radius, num_sides=60):
"""
Draw a circle
"""
angle = 360. / num_sides
side_length = 2. * radius * math.sin(math.radians(angle))
self.draw_polygon(num_sides, side_length)
def get_int(prompt, lo=None, hi=None):
while True:
try:
val = int(raw_input(prompt))
if (lo is None or lo <= val) and (hi is None or val <= hi):
return val
except ValueError:
pass
def do_menu(prompt, options):
print(prompt)
for i,opt in enumerate(options, 1):
print(" {:>2}: {}".format(i, opt))
return get_int("? ", 1, len(options)) - 1
def test_SimpleTurtle():
bob = SimpleTurtle(shape="turtle")
while True:
choice = do_menu("Please choose a draw option:", ["draw a square", "draw a polygon", "draw a circle", "quit"])
if choice == 0:
side_length = random.randint(10, 50)
bob.draw_square(side_length)
elif choice == 1:
sides = random.randint(5, 12)
side_length = random.randint(6, 30)
bob.draw_polygon(sides, side_length)
elif choice == 2:
radius = random.randint(8, 40)
bob.draw_circle(radius)
else:
break
if __name__ == '__main__':
test_SimpleTurtle()