如何将此示例从 python2 转换为 python3

Posted 2023-02-23

【中文标题】如何将此示例从 python2 转换为 python3

【英文标题】：How to convert this example from python2 to python3

【发布时间】：2018-05-30 18:08:58

【问题描述】：

我正在尝试将 github 中的一个工作示例从 python2 转换为 python3，但遇到了一个我不明白的问题。

原文是https://gist.github.com/EugeneBakin/76c8f9bcec5b390e45df 我应用以下补丁并收到有关 SampleApp init 方法的参数过多的错误消息。由于我不明白为什么当唯一的调用根本没有参数时，原始版本有它的 *args 和 **kwargs，所以对我来说没有什么意义。但它适用于 python2，所以我希望它也适用于 python3，因为我认为这种用法很有用。

但是，这可能无关紧要，因为错误消息上的堆栈跟踪不包括该调用或任何与此相关的调用。另一个谜题。

我想解决这个问题，而不是盲目地删除参数，因为当我在实际用例中应用它时可能需要一些参数。

我还想删除作为 * 的导入，因为我认为它很危险并且隐藏了对读者有用的信息。

补丁：

--- VSFrame.py  2017-12-16 14:30:33.458923856 -0800
+++ VSFrame3.py 2017-12-16 15:01:21.914423486 -0800
@@ -1,21 +1,21 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
-from Tkinter import *   # from x import * is bad practice
-from ttk import *
+import tkinter as tk
+import tkinter.ttk as ttk

 # http://tkinter.unpythonic.net/wiki/VerticalScrolledFrame

-class VerticalScrolledFrame(Frame):
+class VerticalScrolledFrame(ttk.Frame):
     """A pure Tkinter scrollable frame that actually works!
     * Use the 'interior' attribute to place widgets inside the scrollable frame
     * Construct and pack/place/grid normally
     * This frame only allows vertical scrolling
     """
     def __init__(self, parent, *args, **kw):
-        Frame.__init__(self, parent, *args, **kw)            
+        super().__init__(self, parent, *args, **kw)            

         # create a canvas object and a vertical scrollbar for scrolling it
-        vscrollbar = Scrollbar(self, orient=VERTICAL)
+        vscrollbar = ttk.Scrollbar(self, orient=VERTICAL)
         vscrollbar.pack(fill=Y, side=RIGHT, expand=FALSE)
         canvas = Canvas(self, bd=0, highlightthickness=0,
                         yscrollcommand=vscrollbar.set)
@@ -51,9 +51,9 @@

 if __name__ == "__main__":

-    class SampleApp(Tk):
+    class SampleApp(tk):
         def __init__(self, *args, **kwargs):
-            root = Tk.__init__(self, *args, **kwargs)
+            root = tk.__init__(self, *args, **kwargs)


             self.frame = VerticalScrolledFrame(root)

在威廉的评论之后（谢谢），现在是

--- VSFrame.py  2017-12-16 14:30:33.458923856 -0800
+++ VSFrame3.py 2017-12-16 16:04:00.938380716 -0800
@@ -1,21 +1,21 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
-from Tkinter import *   # from x import * is bad practice
-from ttk import *
+import tkinter as tk
+import tkinter.ttk as ttk

 # http://tkinter.unpythonic.net/wiki/VerticalScrolledFrame

-class VerticalScrolledFrame(Frame):
+class VerticalScrolledFrame(ttk.Frame):
     """A pure Tkinter scrollable frame that actually works!
     * Use the 'interior' attribute to place widgets inside the scrollable frame
     * Construct and pack/place/grid normally
     * This frame only allows vertical scrolling
     """
     def __init__(self, parent, *args, **kw):
-        Frame.__init__(self, parent, *args, **kw)            
+        super().__init__(self, parent, *args, **kw)            

         # create a canvas object and a vertical scrollbar for scrolling it
-        vscrollbar = Scrollbar(self, orient=VERTICAL)
+        vscrollbar = ttk.Scrollbar(self, orient=VERTICAL)
         vscrollbar.pack(fill=Y, side=RIGHT, expand=FALSE)
         canvas = Canvas(self, bd=0, highlightthickness=0,
                         yscrollcommand=vscrollbar.set)
@@ -51,10 +51,9 @@

 if __name__ == "__main__":

-    class SampleApp(Tk):
+    class SampleApp(tk.Tk):
         def __init__(self, *args, **kwargs):
-            root = Tk.__init__(self, *args, **kwargs)
-
+            root = tk.TK.__init__(self, *args, **kwargs)

             self.frame = VerticalScrolledFrame(root)
             self.frame.pack()

【问题讨论】：

应该是+ class SampleApp(tk.Tk):

@Willem 这让我更进一步，但谢谢。现在它抱怨 module.__init__() 的第一个参数必须是 str，而不是 SampleApp。

用 Python3 安装了程序2to3，它可以将许多元素从 Python 2 转换为 Python 3。

【参考方案1】：

我让它更接近https://docs.python.org/3.5/library/tkinter.html#a-simple-hello-world-program 中的风格，让它工作起来

完整来源如下。

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import tkinter as tk
import tkinter.ttk as ttk

# Python3 version of http://tkinter.unpythonic.net/wiki/VerticalScrolledFrame

class VerticalScrolledFrame(ttk.Frame):
    """A pure Tkinter scrollable frame that actually works!
    * Use the 'interior' attribute to place widgets inside the scrollable frame
    * Construct and pack/place/grid normally
    * This frame only allows vertical scrolling
    """
    def __init__(self, parent):
        super().__init__(parent)

        # create a canvas object and a vertical scrollbar for scrolling it
        vscrollbar = ttk.Scrollbar(self, orient=tk.VERTICAL)
        vscrollbar.pack(fill=tk.Y, side=tk.RIGHT, expand=tk.FALSE)
        canvas = tk.Canvas(self, bd=0, highlightthickness=0,
                        yscrollcommand=vscrollbar.set)
        canvas.pack(side=tk.LEFT, fill=tk.BOTH, expand=tk.TRUE)
        vscrollbar.config(command=canvas.yview)

        # reset the view
        canvas.xview_moveto(0)
        canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = interior = ttk.Frame(canvas)
        interior_id = canvas.create_window(0, 0, window=interior,
                                           anchor=tk.NW)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            canvas.config(scrollregion="0 0 %s %s" % size)
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the canvas's width to fit the inner frame
                canvas.config(width=interior.winfo_reqwidth())
        interior.bind('<Configure>', _configure_interior)

        def _configure_canvas(event):
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the inner frame's width to fill the canvas
                canvas.itemconfigure(interior_id, width=canvas.winfo_width())
        canvas.bind('<Configure>', _configure_canvas)


if __name__ == "__main__":

    class SampleApp(ttk.Frame):
        def __init__(self, master=None):
            super().__init__(master)
            self.create_widgets()

        def create_widgets(self):
            self.frame = VerticalScrolledFrame(root)
            self.frame.pack()
            self.label = ttk.Label(text="Shrink the window to activate the scrollbar.")
            self.label.pack()
            buttons = []
            for i in range(10):
                buttons.append(ttk.Button(self.frame.interior, text="Button " + str(i)))
                buttons[-1].pack()

    root = tk.Tk()
    app = SampleApp(master=root)
    app.mainloop()