使用Itertools循環難度

Question

目前我已使用begin_poly和end_poly然後register_shape在Turtle中定義了許多形狀。我希望能夠將所有這些值放入列表中，並且只需按一下按鈕，就可以在列表中循環，從而更改Turtle形狀。我在Itertools難以實現這一點，並想知道如何實現這一目標。

編輯：我最終得到了它，我將所有值附加到列表中，然後使用計數器來選擇要去哪個索引。

Answer 1

首先，創建發生器：

>>> import itertools 
>>> shape_list = ["square", "triangle", "circle", "pentagon", "star", "octagon"] 
>>> g = itertools.cycle(shape_list) 

然後調用next()只要你想一個又一個。

>>> next(g) 
'square' 
>>> next(g) 
'triangle' 
>>> next(g) 
'circle' 
>>> next(g) 
'pentagon' 
>>> next(g) 
'star' 
>>> next(g) 
'octagon' 
>>> next(g) 
'square' 
>>> next(g) 
'triangle' 

這裏有一個簡單的程序：

import itertools 
shape_list = ["square", "triangle", "circle", "pentagon", "star", "octagon"] 
g = itertools.cycle(shape_list) 
for i in xrange(8): 
    shape = next(g) 
    print "Drawing",shape 

輸出：

Drawing square 
Drawing triangle 
Drawing circle 
Drawing pentagon 
Drawing star 
Drawing octagon 
Drawing square 
Drawing triangle