Python Programming - MCQ Practice Questions

The 'with' statement ensures the file is automatically closed when the block exits, even if an error occurs.

Dictionary comprehension creates {0: 0, 1: 1, 2: 4} where keys are from range(3) and values are their squares.

x = 5 is a class variable. It can be accessed via A.x and modified via A.x = new_value or instance modification.

Lambda functions are functions in Python. type(lambda x: x) returns <class 'function'>.

Variable names cannot start with a digit. '2nd_variable' is invalid because it begins with '2'. Valid names start with a letter or underscore.

In Python 3, the division operator (/) always returns a float, regardless of whether the operands are integers. $\frac{5}{2}$ = 2.5, which is a float.

y = x creates a reference to the same list object. When y.append(4) is called, it modifies the original list. Both x and y point to [1, 2, 3, 4].

The string 'Python' has 6 characters: P-y-t-h-o-n. len() returns the number of characters in a string.

Exponentiation is right-associative. 3 2 2 = 3 (2 2) = 3 ** 4 = 81.

Due to string interning in Python, small strings may be cached and refer to the same object. However, this is an implementation detail. a == b is True, but a is b may vary.

y has a default value of 5. When func(3) is called, x=3 and y=5 (default). The function returns 3 + 5 = 8.

This is a ternary conditional expression. Since 5 > 3 is True, the expression evaluates to 10 (the value before 'if').

List slicing x[1:4] includes indices 1, 2, 3 (but excludes 4). Elements are 2, 3, 4 from the list [1, 2, 3, 4, 5].

The 'in' operator checks if 'a' is a substring of 'banana'. It is present (multiple times), so it returns True.

Dictionaries are mutable. The assignment d['c'] = 3 adds a new key-value pair to the dictionary. d becomes {'a': 1, 'b': 2, 'c': 3}.

x += 3 is equivalent to x = x + 3. Starting with x=5, after adding 3, x becomes 8.

Tuples are immutable. Attempting to modify a tuple element with x[0] = 5 raises a TypeError: 'tuple' object does not support item assignment.

None and False are distinct objects. None == False evaluates to False. None is a unique singleton object, not equivalent to False or 0.

In Python, when you assign y = x, both variables reference the same list object in memory. When you modify the list using y.append(4), the original list x is also modified because they point to the same object. Therefore, print(x) outputs [1, 2, 3, 4].