if 语句中的 else 分支无法正常工作（python）

Question

I expect the result will be 'Only accepted the numbers between 1 ~ 6' when I input some number like '9', but the else statement is actually ignored and get through.

main.py

def select_class():

  while True:
    try:
      class_number = int(input('Select number below\n (1)12:00~13:30\n (2)13:35~15:05\n (3)15:45~17:15\n (4)17:20~18:50\n (5)18:55~20:30\n (6)20:25~22:00\n---------------\n'))
      class_text = input('Leave a comment if you have\n')
  
  if re.match(r'[1-6]', class_number):
    if class_number == 1:
      class_hr, class_min = '00', '00'
      return class_hr, class_min, class_text
    elif class_number == 2:
      class_hr, class_min = '01', '35'
      return class_hr, class_min, class_text
    elif class_number == 3:
      class_hr, class_min = '03', '45'
      return class_hr, class_min, class_text
    elif class_number == 4:
      class_hr, class_min = '05', '20'
      return class_hr, class_min, class_text
    elif class_number == 5:
      class_hr, class_min = '06', '55'
      return class_hr, class_min, class_text
    elif class_number == 6:
      class_hr, class_min = '08', '30'
      return class_hr, class_min, class_text
  else:
    print('Only accepted the numbers between 1 ~ 6')
    return class_number
except ValueError:
  pass

terminal:

$ py main.py

Select number below

(1)12:00~13:30

(2)13:35~15:05

(3)15:45~17:15

(4)17:20~18:50

(5)18:55~20:30

(6)20:25~22:00

---

$ 9

Leave a comment if you have

$ it failed

Answer 1

I modified the code to the one below:

def select_class():

while True:
 try:
  class_number = input('Select number below\n (1)12:00~13:30\n (2)13:35~15:05\n (3)15:45~17:15\n (4)17:20~18:50\n (5)18:55~20:30\n (6)20:25~22:00\n---------------\n')

  if int(class_number) == 1:
    class_hr, class_min = '00', '00'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  elif int(class_number) == 2:
    class_hr, class_min = '01', '35'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  elif int(class_number) == 3:
    class_hr, class_min = '03', '45'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  elif int(class_number) == 4:
    class_hr, class_min = '05', '20'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  elif int(class_number) == 5:
    class_hr, class_min = '06', '55'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  elif int(class_number) == 6:
    class_hr, class_min = '08', '30'
    class_text = input('Leave a comment if you have\n')
    return class_hr, class_min, class_text
  else:
    print('Only accepted the numbers between 1 ~ 6')
    continue
except ValueError:
  pass

It works but still looks redundant somewhat.

Answer 2

Syntax for re.match(pattern, string)

So the code re.match(r'[1-6]', class_number) is always throwing an exception.

Change your code to below

class_number = input( 'Select number below\n (1)12:00~13:30\n (2)13:35~15:05\n (3)15:45~17:15\n (4)17:20~18:50\n (5)18:55~20:30\n (6)20:25~22:00\n---------------\n') class_text = input('Leave a comment if you have\n')

========

9 Leave a comment if you have 343 <class 'str'> Only accepted the numbers between 1 ~ 6

Answer 3

Your match needs to match against a string.

import re
while True:
    class_number = input('Select number ...')
    class_text = input('Leave a comment if you have\n')
    if re.match(r'[1-6]', class_number):
        if class_number == '1':
            class_hr, class_min = '00', '00'
            return class_hr, class_min, class_text
        # ...
    else:
        print('Only accepted the numbers between 1 ~ 6')

As your code is written, your re.match always returns True , so your else code is never reached.

If you want to catch bad class_number immediately, then consider:

while True:
    class_number = ''
    while True:
        class_number = input('Select number: '))
        if re.match(r'[1-6]', class_number):
            break
        print('Only accept numbers 1 through 6')
    class_text = input('Leave a comment if you have: \n')
    if class_number == '1':
        class_hr, class_min = '00', '00'
    elif class_number == 2:
        class_hr, class_min = '01', '35'
    elif class_number == 3:
        class_hr, class_min = '03', '45'
    elif class_number == 4:
        class_hr, class_min = '05', '20'
    elif class_number == 5:
        class_hr, class_min = '06', '55'
    elif class_number == 6:
        class_hr, class_min = '08', '30'
    return class_hr, class_min, class_text