如何向 Tkinter 按鈕命令中傳遞引數
Tkinter 按鈕中的 command 選項是當使用者按下按鈕後觸發的命令。有些情況下，你還需要向 command 中傳遞引數，但是你卻不能像下面例子中這樣簡單的傳遞引數，
button = tk.Button(app, text="Press Me", command=action(args))
我們將來介紹兩種不同的向 command 中傳遞引數的方法，
通過 partials 向 Tkinter 按鈕命令傳遞引數
在 Python Tkinter 教程-按鈕中演示的那樣, 你可以通過使用 functools 模組中的 partial 物件來傳遞引數。
from sys import version_info
if version_info.major == 2:
import Tkinter as tk
elif version_info.major == 3:
import tkinter as tk
from functools import partial
app = tk.Tk()
labelExample = tk.Button(app, text="0")
def change_label_number(num):
counter = int(str(labelExample['text']))
counter += num
labelExample.config(text=str(counter))
buttonExample = tk.Button(app, text="Increase", width=30,
command=partial(change_label_number, 2))
buttonExample.pack()
labelExample.pack()
app.mainloop()
buttonExample = tk.Button(app, text="Increase", width=30,
command=partial(change_label_number, 2))
partial(change_label_numer, 2) 返回了一個可以來呼叫的物件，在引用的時候它跟一個函式 func 很類似。
通過 lambda 函式向 Tkinter 按鈕命令傳遞引數
你也可以通過 Python 的 lambda 操作符或者函式來建立一個臨時的、一次性的簡單函式用以按鈕被按下時候來呼叫。
from sys import version_info
if version_info.major == 2:
import Tkinter as tk
elif version_info.major == 3:
import tkinter as tk
app = tk.Tk()
labelExample = tk.Button(app, text="0")
def change_label_number(num):
counter = int(str(labelExample['text']))
counter += num
labelExample.config(text=str(counter))
buttonExample = tk.Button(app, text="Increase", width=30,
command=lambda: change_label_number(2))
buttonExample.pack()
labelExample.pack()
app.mainloop()
lambda 函式的語法如下，
lambda: argument_list: expression
具體的通過 lamda 函式傳遞引數的語句是，
buttonExample = tk.Button(app, text="Increase", width=30,
command=lambda: change_label_number(2))
Founder of DelftStack.com. Jinku has worked in the robotics and automotive industries for over 8 years. He sharpened his coding skills when he needed to do the automatic testing, data collection from remote servers and report creation from the endurance test. He is from an electrical/electronics engineering background but has expanded his interest to embedded electronics, embedded programming and front-/back-end programming.
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