用python的tkinter做的简单计算器

代码：

import tkinter as tk


def button_click(item):
    global expression
    expression = expression + str(item)
    input_text.set(expression)


def button_clear():
    global expression
    expression = ""
    input_text.set("")


def button_equal():
    global expression
    try:
        result = str(eval(expression))
        input_text.set(result)
        expression = ""
    except:
        input_text.set("错误")
        expression = ""


root = tk.Tk()
root.title("简单计算器")
root.geometry("390x500")
root.resizable(False, False)

expression = ""

input_text = tk.StringVar()

input_frame = tk.Frame(root, width=300, height=50, bd=0, highlightbackground="black", highlightcolor="black",
                       highlightthickness=2)
input_frame.pack(side=tk.TOP)

input_field = tk.Entry(input_frame, font=('arial', 18, 'bold'), textvariable=input_text, width=50, bg="#eee", bd=0,
                       justify=tk.RIGHT)
input_field.grid(row=0, column=0)
input_field.pack(ipady=10)

button_frame = tk.Frame(root, width=300, height=300)
button_frame.pack()

buttons = [
    ('7', 1, 0), ('8', 1, 1), ('9', 1, 2), ('/', 1, 3),
    ('4', 2, 0), ('5', 2, 1), ('6', 2, 2), ('*', 2, 3),
    ('1', 3, 0), ('2', 3, 1), ('3', 3, 2), ('-', 3, 3),
    ('C', 4, 0), ('0', 4, 1), ('=', 4, 2), ('+', 4, 3)
]

for (text, row, col) in buttons:
    if text == '=':
        button = tk.Button(button_frame, text=text, font=('arial', 18, 'bold'), padx=25, pady=25, bd=8,
                           command=button_equal)
    elif text == 'C':
        button = tk.Button(button_frame, text=text, font=('arial', 18, 'bold'), padx=25, pady=25, bd=8,
                           command=button_clear)
    else:
        button = tk.Button(button_frame, text=text, font=('arial', 18, 'bold'), padx=25, pady=25, bd=8,
                           command=lambda item=text: button_click(item))
    button.grid(row=row, column=col)

root.mainloop()

解释：

计算的核心部分是用了eval函数

str(eval(expression))

 

截图：

运行：

 

改进：

可以把计算器做得复杂，把各种高级数学运算都加进去。