How can I use a conditional expression (expression with if and else) in a list comprehension? [duplicate]

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x if y else z is the syntax for the expression you’re returning for each element. Thus you need:

[ x if x%2 else x*100 for x in range(1, 10) ]

The confusion arises from the fact you’re using a filter in the first example, but not in the second. In the second example you’re only mapping each value to another, using a ternary-operator expression.

With a filter, you need:

[ EXP for x in seq if COND ]

Without a filter you need:

[ EXP for x in seq ]

and in your second example, the expression is a “complex” one, which happens to involve an if-else.

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