符号“？”是什么意思？ 在蟒蛇？

Question

In my code that I was working on, my teacher used symbol.? Can anyone tell what is meaning of symbol ! in this code?

n! = (n-1)! * n
sum(n) = sum(n-1) + n

Answer 1

If you actually ran the code you would have seen there is a syntax error:

>>> n = 1
>>> n! = (n-1)! * n
  File "<stdin>", line 1
    n! = (n-1)! * n
     ^
SyntaxError: invalid syntax

You cannot have a ! in a variable name.

This snippet is most probably pseudo-code with factorials for practicing recursion or something like that.