Why is "return 100 if i <10 else pass" not valid in python?

Question

Everything

 def foo(i): return 100 if i < 10 else pass return 200 if i < 20 else pass return 1 

Why does this not work in python? I believe this code might work the same way:

 def foo(i): if i < 10: return 100 elif i < 20: return 200 else: return 1 

Thanks!

Answer 1

return 100 if i < 10 else pass

you should read it as return (100 if i < 10 else pass) so pass not a value

Answer 2

In the documentation, you will see that the "ternary operator" should look like this:

 conditional_expression ::= or_test ["if" or_test "else" expression] expression ::= conditional_expression | lambda_expr 

and pass is statement not an expression

Answer 3

read your code as follows:

 return (100 if (i < 10) else pass) 

pass is not a value that you can return. The following code will work:

 def foo(i): return 100 if i < 10 else (200 if i < 20 else 1) 

Answer 4

pass is a null operation, that is, when it is executed, nothing happens. It is useful as a placeholder if the statement is required syntactically, but the code should not be executed. It should not be used as part of any logic.

Answer 5

You should read that you work like

 def foo(i): if i < 10: return 100 else: return pass if i < 20: return 200 else: return pass return 1 

return 100 if i < 10 else pass not an "if" expression, it is a ternary operator