python制作简单计算器功能

本文实例为大家分享了python实现简单计算器功能的具体代码，供大家参考，具体内容如下

效果如图：

主要思路：

用列表保存按下的键，按下等于，转换为字符串，利用内置函数eval计算字符串的值。

代码：

from tkinter import *
 
W = 280 #窗口宽度
H = 460 #窗口高度
process_H = 110 #显示运算过程的标签高度
result_H = 50   #显示运算结果的标签高度
msFont = '微软雅黑' #字体
fontSize = 20 #字体大小
 
btnBoderWidth = 0.5 #边框宽度
btnColor = '#4F4F4F' #按钮颜色
btnWidth = 70 #按钮宽度
btnHeight = 60 #按钮高度
 
mainWindows = Tk()
mainWindows.title('计算器')
mainWindows.minsize(W,H)
 
str_process = StringVar()
str_process.set("")
str_result = StringVar()
str_result.set("0")
 
process = Label(mainWindows,font=(msFont,fontSize),bg='orange',anchor='se',wraplength='280',textvariable=str_process)
process.place(width=W,height=process_H) #显示运算过程的标签
result = Label(mainWindows,font=(msFont,fontSize+10),bg='orange',anchor='se',textvariable=str_result)
result.place(y=process_H,width=W,height=result_H) #显示运算结果的标签
 
button_AC = Button(mainWindows,font=(msFont,fontSize),text='AC',fg='orange',bd=btnBoderWidth,command=lambda :clickAC())
button_AC.place(x=0,y=process_H+result_H,width=btnWidth,height=btnHeight)
button_back = Button(mainWindows,font=(msFont,fontSize),text='←',fg=btnColor,bd=btnBoderWidth,command=lambda :clickBack())
button_back.place(x=btnWidth,y=process_H+result_H,width=btnWidth,height=btnHeight)
button_div = Button(mainWindows,font=(msFont,fontSize),text='÷',fg=btnColor,bd=btnBoderWidth,command=lambda :clickOper('/'))
button_div.place(x=btnWidth*2,y=process_H+result_H,width=btnWidth,height=btnHeight)
button_mul = Button(mainWindows,font=(msFont,fontSize),text='×',fg=btnColor,bd=btnBoderWidth,command=lambda :clickOper('*'))
button_mul.place(x=btnWidth*3,y=process_H+result_H,width=btnWidth,height=btnHeight)
 
button_7 = Button(mainWindows,font=(msFont,fontSize),text='7',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('7'))
button_7.place(x=0,y=process_H+result_H+btnHeight,width=btnWidth,height=btnHeight)
button_8 = Button(mainWindows,font=(msFont,fontSize),text='8',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('8'))
button_8.place(x=btnWidth,y=process_H+result_H+btnHeight,width=btnWidth,height=btnHeight)
button_9 = Button(mainWindows,font=(msFont,fontSize),text='9',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('9'))
button_9.place(x=btnWidth*2,y=process_H+result_H+btnHeight,width=btnWidth,height=btnHeight)
button_minus = Button(mainWindows,font=(msFont,fontSize),text='-',fg=btnColor,bd=btnBoderWidth,command=lambda :clickOper('-'))
button_minus.place(x=btnWidth*3,y=process_H+result_H+btnHeight,width=btnWidth,height=btnHeight)
 
button_4 = Button(mainWindows,font=(msFont,fontSize),text='4',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('4'))
button_4.place(x=0,y=process_H+result_H+btnHeight*2,width=btnWidth,height=btnHeight)
button_5 = Button(mainWindows,font=(msFont,fontSize),text='5',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('5'))
button_5.place(x=btnWidth,y=process_H+result_H+btnHeight*2,width=btnWidth,height=btnHeight)
button_6 = Button(mainWindows,font=(msFont,fontSize),text='6',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('6'))
button_6.place(x=btnWidth*2,y=process_H+result_H+btnHeight*2,width=btnWidth,height=btnHeight)
button_add = Button(mainWindows,font=(msFont,fontSize),text='+',fg=btnColor,bd=btnBoderWidth,command=lambda :clickOper('+'))
button_add.place(x=btnWidth*3,y=process_H+result_H+btnHeight*2,width=btnWidth,height=btnHeight)
 
button_1 = Button(mainWindows,font=(msFont,fontSize),text='1',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('1'))
button_1.place(x=0,y=process_H+result_H+btnHeight*3,width=btnWidth,height=btnHeight)
button_2 = Button(mainWindows,font=(msFont,fontSize),text='2',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('2'))
button_2.place(x=btnWidth,y=process_H+result_H+btnHeight*3,width=btnWidth,height=btnHeight)
button_3 = Button(mainWindows,font=(msFont,fontSize),text='3',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('3'))
button_3.place(x=btnWidth*2,y=process_H+result_H+btnHeight*3,width=btnWidth,height=btnHeight)
button_equal = Button(mainWindows,font=(msFont,fontSize),text='=',bg='orange',fg=btnColor,bd=btnBoderWidth,command=lambda :clickEqual())
button_equal.place(x=btnWidth*3,y=process_H+result_H+btnHeight*3,width=btnWidth,height=btnHeight*2)
 
button_percent = Button(mainWindows,font=(msFont,fontSize),text='%',fg=btnColor,bd=btnBoderWidth,command=lambda :clickOper("%"))
button_percent.place(x=0,y=process_H+result_H+btnHeight*4,width=btnWidth,height=btnHeight)
button_0 = Button(mainWindows,font=(msFont,fontSize),text='0',fg=btnColor,bd=btnBoderWidth,command=lambda :clickNum('0'))
button_0.place(x=btnWidth,y=process_H+result_H+btnHeight*4,width=btnWidth,height=btnHeight)
button_point = Button(mainWindows,font=(msFont,fontSize),text='.',fg=btnColor,bd=btnBoderWidth,command=lambda :clickPoint())
button_point.place(x=btnWidth*2,y=process_H+result_H+btnHeight*4,width=btnWidth,height=btnHeight)
 
process_list = []
s_result = ""
isNum = [False] #上一位按下的是否是数字
point = [True] #小数点使用情况
def clickNum(num):  #按下数字
    isNum.append(True)
    point.append(point[-1]) #按下数字，小数点的标志不变
    process_list.append(num)
    s_process = "".join(process_list)
    str_process.set(s_process)
 
def clickOper(sign):#按下运算符
    global isNum,point
    if isNum[-1]:
        process_list.append(sign)
        isNum.append(False)
        point.append(True) #按下运算符，小数点标志为可以按下小数点
    else:
        process_list.pop()
        process_list.append(sign)
    s_process = "".join(process_list)
    str_process.set(s_process)
 
def clickEqual():#按下等于
    global s_result
    s_process = "".join(process_list)
    s_result = eval(s_process)
    s_result = str(s_result)[0:11] #结果只显示11位
    str_process.set(s_process)
    str_result.set(s_result)
 
def clickAC():#按下清除
    global s_result,isNum,point
    s_result = "0"
    isNum = [False]  #状态回到初始时候
    point = [True]
    process_list.clear()
    str_result.set(s_result)
    str_process.set("")
def clickBack(): #按下退格键
    global point, isNum
    if len(process_list) > 0:
        isNum.pop(-1) #删除最后一位的状态
        point.pop(-1)
        process_list.pop()
        s_process = "".join(process_list)
        str_process.set(s_process)
 
def clickPoint():#按下小数点
    global point,isNum
    if isNum[-1] and point[-1]:
        process_list.append(".")
        s_process = "".join(process_list)
        str_process.set(s_process)
        isNum.append(False)
        point.append(False)
 
mainWindows.mainloop()

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