Conditional operator in Python? [duplicate]

Question

This question already has answers here:

Does Python have a ternary conditional operator? (32 answers)

Closed 7 years ago.

do you know if Python supports some keyword or expression like in C++ to return values based on if condition, all in the same line (The C++ if expressed with the question mark ?)

// C++
value = ( a > 10 ? b : c )

• Roger Pate: That C++ operator is called the "conditional operator" or the "ternary operator".

Answer 1

value = b if a > 10 else c

For Python 2.4 and lower you would have to do something like the following, although the semantics isn't identical as the short circuiting effect is lost:

value = [c, b][a > 10]

There's also another hack using 'and ... or' but it's best to not use it as it has an undesirable behaviour in some situations that can lead to a hard to find bug. I won't even write the hack here as I think it's best not to use it, but you can read about it on Wikipedia if you want.

• anon: I've always wondered what notation they rejected as "too confusing" in favour of this.
• Serge: +1, You can use this kind of 'if' even with lambda expressions!
• Peter Hansen: @Neil, not sure if you're referring to the syntax ultimately chosen, or who said "too confusing", but the PEP summarizes all the rejected alternatives among other info: python.org/dev/peps/pep-0308
• Evgeni Sergeev: They should have used test ? a : b. The reasons cited for its rejection are weak.
• Mercury: +! for Not sharing with us the 'not recomended' way ;)

Answer 2

simple is the best and works in every version.

if a>10: 
 value="b"
else: 
 value="c"

• Dwayne Robinson: Sadly this block form if a then b else c and the functional immediate form b if a else c are brain bendingly inverted relative to each other (Python's inverted if is backwards from nearly every other programming language's immediate if 😭).