PyQt5学习6-第一个应用-简单计算器

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结合QPushButton,QLineEdit,QGridLayout能够编写一个简单的计算器软件，可以满足日常基本需求。

calculator

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#!/usr/bin/python3
#-*- coding: utf-8 -*-
import sys
from PyQt5.QtWidgets import QWidget,QPushButton,QLineEdit,QApplication,QGridLayout
class ex(QWidget):
    def __init__(self):
        super(ex, self).__init__()
        self.initUI()
    def initUI(self):
        self.expression = ''
        grid = QGridLayout()
        self.setLayout(grid)
        self.display = QLineEdit('0')
        self.display.setReadOnly(True)
        self.display.setMaxLength(15)
        grid.addWidget(self.display,0,0,1,4)
        names = ['Clear','Back','','Close',
                 '7','8','9','/',
                 '4','5','6','*',
                 '1','2','3','-',
                 '0','.','=','+']
        positions = [(i+1,j) for i in range(5) for j in range(4)]
        for pos, name in zip(positions, names):
            if name == '':
                continue
            button = QPushButton(name)
            button.clicked.connect(self.buttonClicked)
            grid.addWidget(button, *pos)
        self.setWindowTitle('Calcular')
        self.show()
    def buttonClicked(self):
        text = self.sender().text()
        if text in '+-*/':
            self.expression = self.expression + text
        elif text == '=':
            self.expression = str(eval(self.expression))
        elif text == 'Back':
            self.expression = self.expression[0:len(self.expression)-1]
        elif text == 'Clear':
            self.expression = '0'
        elif text == 'Close':
            self.close()
        else:
            self.expression = text if self.expression == '0' else  self.expression+text
        self.display.setText(self.expression)
if __name__ == '__main__':
    app = QApplication(sys.argv)
    e = ex()
    sys.exit(app.exec_())

结果

calculator