There are two distinct but similar-looking syntaxes involved here, conditional expressions and list comprehension filter clauses.
A conditional expression is of the form
x if y else z. This syntax isn’t related to list comprehensions. If you want to conditionally include one thing or a different thing in a list comprehension, this is what you would use:
var_even = [x if x%2==0 else 'odd' for x in var] # ^ "if" over here for "this or that"
A list comprehension filter clause is the
if thing in
elem for x in y if thing. This is part of the list comprehension syntax, and it goes after the
for clause. If you want to conditionally include or not include an element in a list comprehension, this is what you would use:
var_even = [x for x in var if x%2==0] # ^ "if" over here for "this or nothing"