如何用python做一个简单好用的计算器

1 ui设计
使用qt designer ,按装anaconda后,在如下路径找到:

conda3.05\Library\bin

designer.exe文件,双击启动:如何用python做一个简单好用的计算器
创建窗体,命名为XiaoDing,整个的界面如下所示:
如何用python做一个简单好用的计算器
qt 设计器提供的常用控件基本都能满足开发需求,通过拖动左侧的控件,很便捷的就能搭建出如下的UI界面,比传统的手写控件代码要方便很多。

最终设计的计算器XiaoDing界面如下,
如何用python做一个简单好用的计算器
比如,其中一个用于计算器显示的对象:lcdNumber,对象的类型为:LCD Number。右侧为计算器中用到的所有对象。如何用python做一个简单好用的计算器
如何用python做一个简单好用的计算器
2 转py文件
使用如下命令,将设计好的ui文件转为py文件

pyuic5 -o ./calculator/MainWindow.py ./calculator/mainwindow.ui

3 计算器实现逻辑
导入库:

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *

import operator

from MainWindow import Ui_MainWindow

主题代码逻辑很精简:

# Calculator state.
READY = 0
INPUT = 1


class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.setupUi(self)

        # Setup numbers.
        for n in range(0, 10):
            getattr(self, 'pushButton_n%s' % n).pressed.connect(lambda v=n: self.input_number(v))

        # Setup operations.
        self.pushButton_add.pressed.connect(lambda: self.operation(operator.add))
        self.pushButton_sub.pressed.connect(lambda: self.operation(operator.sub))
        self.pushButton_mul.pressed.connect(lambda: self.operation(operator.mul))
        self.pushButton_div.pressed.connect(lambda: self.operation(operator.truediv))  # operator.div for Python2.7

        self.pushButton_pc.pressed.connect(self.operation_pc)
        self.pushButton_eq.pressed.connect(self.equals)

        # Setup actions
        self.actionReset.triggered.connect(self.reset)
        self.pushButton_ac.pressed.connect(self.reset)

        self.actionExit.triggered.connect(self.close)

        self.pushButton_m.pressed.connect(self.memory_store)
        self.pushButton_mr.pressed.connect(self.memory_recall)

        self.memory = 0
        self.reset()

        self.show()

基础方法:

def input_number(self, v):
        if self.state == READY:
            self.state = INPUT
            self.stack[-1] = v
        else:
            self.stack[-1] = self.stack[-1] * 10 + v

        self.display()

    def display(self):
        self.lcdNumber.display(self.stack[-1])

按钮RE,M, RE对应的实现逻辑:

    def reset(self):
        self.state = READY
        self.stack = [0]
        self.last_operation = None
        self.current_op = None
        self.display()

    def memory_store(self):
        self.memory = self.lcdNumber.value()

    def memory_recall(self):
        self.state = INPUT
        self.stack[-1] = self.memory
        self.display()

+,-,x,/,/100对应实现方法:

def operation(self, op):
        if self.current_op:  # Complete the current operation
            self.equals()

        self.stack.append(0)
        self.state = INPUT
        self.current_op = op

    def operation_pc(self):
        self.state = INPUT
        self.stack[-1] *= 0.01
        self.display()

=号对应的方法实现:

 def equals(self):
        if self.state == READY and self.last_operation:
            s, self.current_op = self.last_operation
            self.stack.append(s)

        if self.current_op:
            self.last_operation = self.stack[-1], self.current_op

            try:
                self.stack = [self.current_op(*self.stack)]
            except Exception:
                self.lcdNumber.display('Err')
                self.stack = [0]
            else:
                self.current_op = None
                self.state = READY
                self.display()

main函数:

if __name__ == '__main__':
    app = QApplication([])
    app.setApplicationName("XiaoDing")

    window = MainWindow()
    app.exec_()

启动后的界面如下:
如何用python做一个简单好用的计算器
简单好玩的计算器就这样完成了
最近建了一个互相交流学习的python扣扣裙609616831,欢迎各路大神萌新一起来讨论python知识以及遇到的一些难题

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