如何检查字符串是否包含字符和空格（空字符）？

Question

I've created a "virtual signboard" program for fun. I can get it to work if the input is only made out of characters using input_string.isalpha(), however if I input a string with a space or empty character (ex:hello world), it goes into "else" and doesn't run the get_letter function.

I've omitted parts from the get_letter function to save space but it goes from a to z.

This is the program:

import time

def get_letter(letters):
    while True:
        for i in letters:
            if i.lower()=='a':
                print('  *  ')
                time.sleep(0.1)
                print(' ***')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('*****')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('     ')
                time.sleep(0.1)
            elif i.lower()=='b':
                print('****')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('****')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('*   *')
                time.sleep(0.1)
                print('****')
                time.sleep(0.1)
                print('     ')
                time.sleep(0.1)
                
[goes all the way to z]

            elif i.lower() == ' ':
                print('')
                time.sleep(0.1)
                print('')
                time.sleep(0.1)
                print('')
                time.sleep(0.1)
                print('')
                time.sleep(0.1)
                print('')
                time.sleep(0.1)
                print('')
                time.sleep(0.1)

def instructions():
    #instructions
    print('Welcome to  virtual signboard\n')
    time.sleep(0.5)
    print('Type in what you would like to display on your virtual signboard. Start and end with a space.')
    time.sleep(0.5)
    print('Ex:" hello world "')
    time.sleep(0.5)
    global input_string
    input_string=input('Enter the word(s) you would like displayed:\n')
    
instructions()

try:
    if input_string.isalpha(): #check if input is a to z characters
        get_letter(input_string)
    else:
        print('\nOnly a-z characters are accepted')
        instructions()
except KeyboardInterrupt: #to stop signboard press ctrl c
    sys.exit()

Answer 1

You have to change the line with an input() function. We will add a while loop and below it the input() . If input splitter from the newlines and spaces is the same as the input, it means that input_string is proper and the while loop will broke. If it is not, the user will have to enter a string that does not contain those characters.

while True:
    input_string = input('Enter the word(s) you would like displayed:\n')
    if ''.join(input_string.split()) == input_string:
        break

Answer 2

Id do replace() :

inp = input('Enter your text'),replace(' ','')