Week 3 Unit 4: Self-test

Question 1

What is the purpose of a safe dictionary access?

Note: There are 3 correct answers to this question.

Safe dictionary access reduces the probability of being infected by a virus.

❌

Safe dictionary access prevents access to keys, that do not exist.

✅

Safe dictionary access limits the probability of wrong user input.

❌

Safe dictionary access hides the actual access behind a condition, which checks the existence of the key.

✅

Safe dictionary access should be used if it is not clear which keys are used to access a dictionary, for example, if the key is taken by user input.

✅

Question 2

What is the value of variable a after the following statements have been executed?

key does not exist

❌

123

❌

123 : "Harry"

❌

"Harry"

✅

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