Peer Instruction: Booleans Multiple Choice Questions¶

Q-1: In the following expression, which parts are evaluated?

(7 > 2) or ( (9 < 2) and (8 > 3) )

Only (7>2)
Correct! Python evaluates from left to right. If the first part of an expression containing 'or' is True, the truth of the statement is know.
Only (9<2)
Incorrect! Python evaluates from left to right.
Only (8>3)
Incorrect! Python evaluates from left to right.
(7>2) and (8>3)
Incorrect! Python evaluates from left to right.
All the code is evaluated
Incorrect! The (7 > 2) is joined by an or so since (7 > 2) is true, evaluation stops.

Q-2: In the following expression, which parts are evaluated?

( (7 > 2) and (9 < 2) ) or (8 > 3)

Only (7>2)
Incorrect! Python evaluates from left to right and must evaluate both sides of an expression when they are joined by "and".
Only (9<2)
Incorrect! Python evaluates from left to right and must evaluate both sides of an expression when they are joined by "and".
Only (8>3)
Incorrect! Python evaluates from left to right and must evaluate both sides of an expression when they are joined by "and".
(7>2) and (8>3)
Incorrect! Python evaluates from left to right. The ((7 > 2) and (9 < 2)) will be evaluated first.
All the code is evaluated
Correct! The truth of this expression is not established until all parts have been evaluated.