[FIXED] PyQt convert temperature to Celsius and Fahrenheit using one button

Issue

I just started using PyQt5 and so far I'm able to convert celsius to Fahrenheit but I'm a little confused on how to convert to celsius when I type a value in the Fahrenheit lineEdit box, example. How can I check whether there is a value in either box and convert it using a single button?

temperature converter

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(299, 140)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(10, 40, 121, 21))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(160, 40, 121, 21))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(110, 70, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(160, 20, 61, 16))
        self.label_2.setObjectName("label_2")
        self.label_3 = QtWidgets.QLabel(self.centralwidget)
        self.label_3.setGeometry(QtCore.QRect(10, 20, 61, 16))
        self.label_3.setObjectName("label_3")
        self.label_4 = QtWidgets.QLabel(self.centralwidget)
        self.label_4.setGeometry(QtCore.QRect(140, 40, 21, 20))
        self.label_4.setObjectName("label_4")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 299, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)


        self.pushButton.clicked.connect(self.Celsius_Line)




    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Convert"))
        self.label_2.setText(_translate("MainWindow", "Fahrenheit"))
        self.label_3.setText(_translate("MainWindow", "Celsius"))
        self.label_4.setText(_translate("MainWindow", "="))


    def Celsius_Line(self):
        c = str(float(self.lineEdit.text()) * (9/5) + 32 )
        self.lineEdit_2.setText(c)

    def Fahrenheit_Line(self):
        f = str(float(self.lineEdit_2.text()) * (9/5) - 32)
        self.lineEdit.setText(f)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Solution

Modified code, if celcius is empty it will convert from Farenheit. else cel to fareanheit

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(299, 140)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(10, 40, 121, 21))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(160, 40, 121, 21))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(110, 70, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(160, 20, 61, 16))
        self.label_2.setObjectName("label_2")
        self.label_3 = QtWidgets.QLabel(self.centralwidget)
        self.label_3.setGeometry(QtCore.QRect(10, 20, 61, 16))
        self.label_3.setObjectName("label_3")
        self.label_4 = QtWidgets.QLabel(self.centralwidget)
        self.label_4.setGeometry(QtCore.QRect(140, 40, 21, 20))
        self.label_4.setObjectName("label_4")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 299, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)


        self.pushButton.clicked.connect(self.Converteither) #Mod here




    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Convert"))
        self.label_2.setText(_translate("MainWindow", "Fahrenheit"))
        self.label_3.setText(_translate("MainWindow", "Celsius"))
        self.label_4.setText(_translate("MainWindow", "="))


    def Celsius_Line(self):
        c = str(float(self.lineEdit.text()) * (9/5) + 32 )
        self.lineEdit_2.setText(c)

    def Fahrenheit_Line(self):
        f = str(float(self.lineEdit_2.text()) * (9/5) - 32)
        self.lineEdit.setText(f)

    def Converteither(self):
        if self.lineEdit.text() == "":
            f = str(float(self.lineEdit_2.text()) * (9/5) - 32)
            self.lineEdit.setText(f)
        else:
            c = str(float(self.lineEdit.text()) * (9/5) + 32 )
            self.lineEdit_2.setText(c)            


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answered By - Vignesh