import sys
from math import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class Form(QDialog):
def __init__(self, parent=None):
super().__init__(parent)
self.browser = QTextBrowser()
self.lineedit = QLineEdit("Type an expression.")
self.lineedit.selectAll()
layout = QVBoxLayout()
layout.addWidget(self.browser)
layout.addWidget(self.lineedit)
self.setLayout(layout)
self.lineedit.setFocus()
self.lineedit.returnPressed.connect(self.updateUi)
self.setWindowTitle("Calculate")
def updateUi(self):
try:
text = str(self.lineedit.text())
self.browser.append("%s = <b>%s</b>" % (text, eval(text)))
except:
self.browser.append("<font color=red>%s is invalid!</font>" % text)
app = QApplication(sys.argv)
form = Form()
form.show()
app.exec_()
