python - 为什么 if not 操作 == '/' 或 '*' 或 '+' 或 '-' : give me a syntax error,

Question

if not operation == '/' or '*' or '+' or '-':
  print('not a valid answer, try again')
  operation = (input('Please enter what operation you would like to do, / is divide, * is multiply, + is plus and - is minus')

Answer 1

operation = (input('Please enter what operation you would like to do, / is divide, * is multiply, + is plus and - is minus')

您忘记添加第二个右大括号。在这种情况下，只需删除左大括号即可。

此外，您的 if 语句将始终为 True。以下代码将起作用:

if not operation in ['/', '*', '+', '-']: # test if operation is one of /, *, + and -
  print('not a valid answer, try again')
  operation = input('Please enter what operation you would like to do, / is divide, * is multiply, + is plus and - is minus')