0 — Test 604

Correct Answer: B. ['a', 'b', '', 'c']
Explanation: An explicit separator keeps empty fields. split() with no argument splits on runs of whitespace and drops empty strings. ALSO KNOW (related points): • What does map(str, [1, 2]) return in Python 3? → A lazy map iterator object • What does 'Python'[::-1] return? → 'nohtyP' • What does ' a b '.split() return? → ['a', 'b']

Correct Answer: A. TypeError: sequence item 0: expected str instance, int found
Explanation: Use ",".join(map(str, [1, 2, 3])).

Correct Answer: B. It raises ValueError
Explanation: int() accepts only integer text. Use int(float("3.5")) to get 3.

Correct Answer: B. find returns -1; index raises ValueError
Explanation: Choose find when a missing substring is a normal case, and index when it is an error. ALSO KNOW (related points): • What happens with a, b = [1, 2, 3]? → ValueError: too many values to unpack • What does int("3.5") do? → It raises ValueError • What is the difference between @staticmethod and @classmethod? → A classmethod receives the class (cls) as its first argument; a staticmethod receives no implicit first argument • What is the difference between print in Python 2 and Python 3? → In Python 3, print is a function and needs parentheses; in Python 2, it was a statement

Correct Answer: D. 1-2-3
Explanation: The * operator unpacks the list into separate arguments.

Correct Answer: C. The block runs only when the file is executed directly, not when it is imported
Explanation: When the file is imported, __name__ is set to the module's name.

Correct Answer: C. No; it prints 10
Explanation: Comprehensions have their own scope in Python 3. In Python 2, the variable leaked. ALSO KNOW (related points): • What does print(*[1, 2, 3], sep='-') print? → 1-2-3

Correct Answer: C. A classmethod receives the class (cls) as its first argument; a staticmethod receives no implicit first argument
Explanation: classmethods are often used as alternative constructors.

Correct Answer: C. No; it is just the conventional name for the first parameter of an instance method
Explanation: Any name works, but using self is a strong convention.

Correct Answer: D. The file is closed when the block exits, even if an exception occurs
Explanation: Context managers implement __enter__ and __exit__.