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[英]How is the global variable being incremented when it's not being directly specified?
[英]Python variable is not being incremented
我正在尝试使用 python (tkinter GUI)制作一个简单的计算器。 但是,当我尝试增加指针变量时,它不起作用。 据我所知,这是因为我的指针变量不是全局变量,我没有将它声明为全局变量。 但即使在我这样做之后,它仍然无法正常工作。 有人可以解释为什么吗?
from tkinter import *
root = Tk()
root.title("Calculator (Simple)")
entrybox = Entry(root, width = 40, borderwidth= 5)
entrybox.grid(row=0, column=0, columnspan=3, padx=10, pady=10)
global pointer
pointer = 0
def button_entry(num):
pointer += 1
number = entrybox.get() + num
entrybox.delete(0, END)
entrybox.insert(0, number)
print(pointer)
global pointer
应位于第一行button_entry
内的 button_entry 内。
You have to put global pointer in the function, not outside, because it says to python interpreter that you need to use a variable that is not described in this function and it's in global scope
from tkinter import *
root = Tk()
root.title("Calculator (Simple)")
entrybox = Entry(root, width = 40, borderwidth= 5)
entrybox.grid(row=0, column=0, columnspan=3, padx=10, pady=10)
pointer = 0
def button_entry(num):
global pointer
pointer += 1
number = entrybox.get() + num
entrybox.delete(0, END)
entrybox.insert(0, number)
print(pointer)
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