函数ID使我的条件无法运行

Question

I created a simple piece of code that counts up and down and display the word Blastoff if the number is bigger/smaller than 0. After defining my function I wanted it to be called when I chose a number but the only output that I receive is the function id as if it was duplicated.

def countdown(n):
    if n <= 0:
        print('Blastoff!')
    else:
         print(n)
         countdown(n-1)

def countup(n):
    if n >= 0:
        print('Blastoff!')
    else:
        print(n)
        countup(n+1)

n = int(input('Pick a number from -10 to 10\n'))
if n > 0:
    print(countdown)
elif n < 0:
    print(countup)
elif n == 0:
    print(countup)

That's the outcome that I receive after I run the code:

Pick a number from -10 to 10
-10
<function countdown at 0x030DA390>

I wanted it to run the countup function instead.

What I'm missing? Thoughts? Cheers.

Answer 1

The issue here is the missing argument.

def countdown(n):
     if n <= 0:
         print('Blastoff!')
     else:
         print(n)
         countdown(n-1)

def countup(n):
    if n >=0:
        print('Blastoff!')
    else:
        print(n)
        countup(n+1)

n = int(input('Pick a number from -10 to 10\n'))
if n > 0:
        print(countdown(n))
elif n < 0:
        print(countup(n))
elif n == 0:
        print(countup(n))

Answer 2

The problem is that you are not passing the argument to the methods:

print(countdown)
print(countup) 

Notice that it should rather have been:

print(countdown(n))
print(countup(n))

Formatted the code as well:

def countdown(n):
    if n <= 0:
      print('Blastoff!')
    else:
      print(n)
      countdown(n-1)

def countup(n):
    if n >= 0:
        print('Blastoff!')
        exit()
    else:
        print(n)
        countup(n+1)

def user_num(n):
    if n > 0:
        print(countdown(n))
    elif n < 0:
        print(countup(n))
    elif n == 0:
        print(countup(n))

if __name__ == '__main__':
    n = int(input('Pick a number from -10 to 10\n'))
    user_num(n)

OUTPUT:

Pick a number from -10 to 10
-10
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
Blastoff!

Process finished with exit code 0