PyQt5 Demo with some solutions to a couple easy job interview questions (palendrome and letter count)

main.py

#!/usr/bin/env python3

import sys
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QMessageBox

def isPalendrome(aString):
    for i in range(len(aString) // 2):
        if aString[i] != aString[len(aString) - 1 - i]:
            return False
    return True

CHAR_SIZE = 1 # In bytes

def countLetters(word):
    letterCount = [0 for _ in range(2 ** (8 * CHAR_SIZE))]
    for c in word:
        if ord(c) > 2 ** (8 * CHAR_SIZE):
            print(f"Warning! Character {c} is outside supported character set!")
        letterCount[ord(c)] += 1
    retString = ""
    for i in range(len(letterCount)):
        if letterCount[i] > 0:
            retString = f"{retString}\nFor letter {chr(i)}, count is {letterCount[i]}"
    return retString

# UI Stuff
def palendromeUIHandler(textBox):
    msg = QMessageBox()
    if isPalendrome(textBox.text()):
        msg.setText(f"Word is {textBox.text()} a palendrome!")
        msg.setIcon(QMessageBox.Information)
    else:
        msg.setText(f"Word {textBox.text()} is NOT a palendrome!")
        msg.setIcon(QMessageBox.Warning)
    msg.exec_()

def letterCountUIHandler(textBox):
    msg = QMessageBox()
    msg.setIcon(QMessageBox.Information)
    msg.setText(countLetters(textBox.text()))
    msg.exec_()

if __name__=='__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = QtWidgets.QWidget()
    window.resize(400, 400)
    window.setWindowTitle("Never Gonna Give You Up")
    layout = QtWidgets.QVBoxLayout()
    layout.addWidget(QtWidgets.QLabel("Palendrome Word:"))
    palendrome = QtWidgets.QLineEdit()
    palendromeButton = QtWidgets.QPushButton("Check Palendrome!")
    palendromeButton.clicked.connect(lambda : palendromeUIHandler(palendrome))
    layout.addWidget(palendrome)
    layout.addWidget(palendromeButton)
    layout.addWidget(QtWidgets.QLabel("Count the letters in this string:"))
    letterCount = QtWidgets.QLineEdit()
    letterCountButton = QtWidgets.QPushButton("Count the letters in this string!")
    letterCountButton.clicked.connect(lambda : letterCountUIHandler(letterCount))
    layout.addWidget(letterCount)
    layout.addWidget(letterCountButton)
    window.setLayout(layout)
    window.show()
    sys.exit(app.exec_())