import sys

from PyQt5 import uic, QtCore, QtGui

Qt = QtCore.Qt

try:
    _encoding = QtGui.QApplication.unicodeUTF8
    def _translate(context,text,disambig):
        return QtGui.QApplication.translate(context,text,disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text ,disambig)

class MyWindow(QtGui.QtWidget):
    def __init__(self):
        super(MyWindow, self).__init__()
        uic.loadUi('calculadora.ui', self)
        self.connect(btn0,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('0'))
        self.connect(btn1,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('1'))
        self.connect(btn2,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('2'))
        self.connect(btn3,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('3'))
        self.connect(btn4,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('4'))
        self.connect(btn5,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('5'))
        self.connect(btn6,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('6'))
        self.connect(btn7,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('7'))
        self.connect(btn8,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('8'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('9'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('/'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('-'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('+'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),lambda:self.aniadir('*'))
        self.connect(btn9,QtCore.SIGNAL('clicked()'),self.evaluar)
        self.show()

def aniadir (self, que):
    actual = self.QLineEdit.text()
    self.QLineEdit.setText(actual+que)

def evaluar(self):
    expr = self.QLineEdit.text()
    resultado = eval(str(expr))
    if type (resultado) in [float, int]:
        self.QLineEdit.setText(str(resultado))

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    window = MyWindow()
    sys.exit(app.exec_())