Python-If语句与input（）在def（）函数内部不起作用

Question

Everything in the code runs properly except def a() and def b() have and if statements that examine and input function though when I run the code it will lead to 'good for you' being printed no matter the input. For instance if I type False or Whatever into the code which should lead to different results, both lead to the response 'good for you' as though the input is always 'True' or 'true' . I haven't been coding for very long so excuse me if this is an obvious fix.

    tsil = ['input',]

while True:
  print('Write A Number (Print "done" When Finished)')
  num = input()
  tsil.append(num)
  print()
  if num == 'done':
    break

if True == True:
  print(tsil)

def a():
  print('you like short lists? (True or False)')
  ans = input()
  if ans == 'True' or 'true':
    return '\ngood for you'
  elif ans == 'False' or 'false':
    return '\nstop making short lists then'
  else:
    return '\nstop printing the wrong things loser'


def b():
  print('you like long lists? (True or False)')
  ans = input()
  if ans == 'True' or 'true':
    return '\ngood for you'
  elif ans == 'False' or 'false':
    return '\nstop making short lists then'
  else:
    return '\nstop printing the wrong things loser'

if len(tsil) < 10:
  print('^ short list large gorge')
  print()
  print(a())
else:
  print('^ big boy list')
  print()
  print(b())

Answer 1

You need to change your if statement from if ans == 'True' or 'true': to if ans == 'True' or ans == 'true':

See below code:

def a():
  print('you like short lists? (True or False)')
  ans = input()
  if ans == 'True' or ans == 'true':   # if ans.lower() == 'true':
    return '\ngood for you'
  elif ans == 'False' or 'false':
    return '\nstop making short lists then'
  else:
    return '\nstop printing the wrong things loser'

Reasoning

If you check ans == 'True' or 'true will always generate 'True' which is 1st value in OR condition.

bool('any value') is always True

Answer 2

Take a look a this line carefully ans == 'True' or 'true'

This will always return True

You can try

print(bool('False' == 'True' or 'true'))
print(bool(-999 == 'True' or 'true'))
print(bool('Unicorn' == 'True' or 'true'))

to see its truth-value.

To solve the issue, you can replace ans == 'True' or 'true' with

if ans in ['True', 'true']:

or

if ans.lower() == 'true':

hope this helps.

Answer 3

if ans == 'True' or 'true'

should be

if ans == 'True' or  ans == 'true'

and same for other similar cases, since if 'non-empty string' evaluates to True

Answer 4

Your problem is that your conditions in the functions are as follows:

ans == 'True' or 'true'

The python interpreter sees it as being:

(ans == 'True') or ('true')

and a non empty string is evaluated to true when used in an if statement.

Change it to this:

ans == 'True' or ans == 'true'