使用onkey（）和字典绘制海龟（python）的错误

Question

我决定根据我收到的建议重做这个问题，这是一个我第一年的作业问题，uni，python编码。我的代码中有bug，无法找到修复它们的方法。错误1乌龟在程序运行时开始画图，即使笔已打开。BUG 2未定义的键，如“s、7、tab”触发空格键功能

着色书

在本任务中，您将创建一个儿童着色游戏，在该游戏中，可以通过围绕形状进行跟踪，然后填充来为给定的图片着色。控件如下所示。

箭头键-将“画笔”（海龟光标）向左、向右、向上或向下移动一个固定的小量。

'z'-撤消最后一步。

“r”、“g”、“b”-将画笔颜色分别更改为红色、绿色或蓝色。（如果您愿意，可以定义更多颜色，但我们希望至少有这三种颜色。）

空格键-切换绘制模式。在初始模式“移动”模式下，“画笔”（乌龟）在屏幕上移动而不绘制。在“绘制”模式下，画笔移动时会留下一条彩色线。最重要的是，当模式从“绘制”更改为“移动”时，画笔绘制的区域将充满颜色。

from turtle import *
from functools import partial 
bgpic("Colour_A_Turkey.gif") # change this to change the picture

#control the accuracy/speed of the drawing 
step_size =8
pensize(4)
penup()

# whenever spacebar is pressed the current state  and next state switch values 
current_state = penup
next_state = pendown
def space_bar():
    global current_state, next_state
    next_state()
    current_state, next_state = next_state, current_state
    #if the current stat is penup fill in with current colour
    if current_state == penup:
        end_fill()
    else:
        begin_fill()
onkey(space_bar, " ")

# undo do a mistake function
def mistake():
    undo()
onkey(mistake, "z")

#using partial function to store the following functions
#so they can be called  as arguments from a dictionary
#movement
strait = partial(fd, step_size)
reverse = partial(bk, step_size)
turn_rt = partial(rt, step_size)
turn_lf = partial(lt, step_size)

#colour
brow = partial(color, "brown")
gree = partial(color, "green")
yell = partial(color, "yellow")
oran = partial(color, "orange")
purp = partial(color, "purple")
red = partial(color, "red")
blue = partial(color, "blue")


#create a dictionary to store all the keys and there abilities 
key_action = {"b" : blue, "r" : red, "p" : purp, "o" : oran,\
          "y" : yell, "g" : gree, "w" : brow, "Right" : turn_rt , "Up" : strait,\
          "Down" : reverse, "Left" : turn_lf, "z" : undo()}

#when a key in then above dictionary
#is pressed it's function  is activated
for pressed_key, activated_key in key_action.items():
    onkey(activated_key, pressed_key)  

#make turtle look for key strokes with predefined function
listen()
#finish
done()

Answer 1

为什么要定义所有的功能？我们可以直接使用：Break the判决为：

key_action = {"b" : "blue", "r" : "red", "p" : "purple", "o" : "orange", "y" : "yellow","g" : "green", "w" : "brown","Right" : rt , "Left": lt, "Up" : fd, "Down" : bk,"z" : undo}


no_input = ["z"]

one_input = ["Right", "Left", "Up", "Down"]

for key in key_action:
    activated_key = key_action[key]
    if key in no_input:
       activated_key()
    elif key in one_input():
        activated_key(step_size)
    else:
        onkey(color(activated_key), key)

Answer 2

你的字典方法是沿着正确的思维方式。但是，您的函数将无法正常运行。使用字典比你想象的要简单。首先，你必须对String有单独的函数，并正确处理它们。因为他们每个人的行为都不同：

# Get rid of the top four lines, they will not work
# All actions mapping
key_action = {"b" : "blue", "r" : "red", "p" : "purple", "o" : "orange",
              "y" : "yellow", "g" : "green", "w" : "brown",
              "Right" : rt , "Left": lt, "Up" : fd, "Down" : bk,
              "z" : undo}
# Note down which are special actions
# Functions with no input
foo = ["z"]
# Function with one input
bar = ["Right", "Left", "Up", "Down"]

# Assuming the input key is get here, I don't use turtle don't know how
# the input is read
key = listen()  # PSEUDOCODE!

# Handle the input
if key in foo:
     foo[key]() # Execute no input function
elif key in bar:
     foo[key](step_size)
else:
     onkey(key_action[key], key)

Answer 3

记住，在Python中，一切都是一个对象，我们的意思是。函数也是对象。我们可以在字典中存储函数，事实上，这正是您在这里想要做的。

turn_lf = lt(step_size )

这里的关键问题是，您希望存储一个调用lt的函数，其中step_size作为参数，但是这里您刚刚调用了lt，其中step_size作为参数，并且存储返回值。

可以说，获得所需内容的最简单方法是使用functools.partial来“绑定”步长参数。

from functools import partial
turn_lf = partial(lt, step_size) # `lt` is not called yet.

# Now, later on, we can do
turn_lf() # and it's just as if we did `lt(step_size)`.
# So now we can store `turn_lf` in a dict, look it up and call it later, etc.

# Similarly for all the other functions you want to make.

（另一个问题是您没有与此保持一致；如果您希望所有内容都在一个判决中进行，那么您还需要为颜色函数指示绑定。幸运的是，这和其他函数一样简单：我们只是让我们的部分（颜色，'棕色'）。

至于“z”：delete，我们没有任何参数绑定到undo。因此，虽然我们可以按照模式编写partial（undo）（注意，没有更多参数，因为我们没有绑定任何内容），但直接编写undo更有意义。

顺便说一句，我们可以简化一下：

for key in key_action:
    pressed_key = key
    activated_key = key_action[key]

对此：

for pressed_key, activated_key in key_action.items():