Week 1 Graded Assignment 1

Course: Jan 2026 - Python

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Question 1

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Identify Operands: Both operands are integers ($5$ and $2$).
2. Identify Operator: Addition ($+$) between two integers results in an integer in Python. ^python-w1-q1-strategy

Procedure

• $5$ is of type int.
• $2$ is of type int.
• 5 + 2 evaluates to $7$, which is an int.

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Question 2

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Python Division Rule: In Python 3, the standard division operator (/) always returns a floating-point number, even if the division is exact (e.g., 4 / 2 is 2.0).

Procedure

• $5 / 2$ evaluates to $2.5$.
• $2.5$ is of type float.

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Question 3

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Mixed Type Promotion: If any operand in an arithmetic operation is a float, the result is promoted to a float.
2. Operator: Exponentiation (**).

Procedure

• $5$ is int, $2.0$ is float.
• $5^{2.0} = 25.0$.
• Type is float.

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Question 4

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Literal Identification: Content enclosed in quotes ("..." or '...') is treated as a string literal.

Procedure

• The expression is enclosed in double quotes.
• No arithmetic is performed inside the string by the interpreter in this context.
• Output is the string object "5 + 2".

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Question 5

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Short-circuiting: In Python, x and y returns $x$ if $x$ is falsy, otherwise it returns $y$. x or y returns $x$ if $x$ is truthy, otherwise it returns $y$.
2. Truthiness: Non-zero integers are truthy.
3. Precedence: and has higher precedence than or. ^short-circuit-logic

Procedure

• 5 and 2: $5$ is truthy, so it returns $2$.
• The expression becomes 2 or "2".
• $2$ is truthy, so or short-circuits and returns $2$.
• $2$ is of type int.

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Question 6

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Subscriptability: Indexing ([...]) is allowed on sequences (like strings, lists, tuples) but not on numeric types like int.

Procedure

• $555$ is an int.
• Integers are not "subscriptable".
• Attempting to index an integer raises a TypeError.

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Question 7

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Sequence Indexing: Strings are sequences. Indexing a string returns a string containing the character at that position.

Procedure

• "555" is a string.
• Index $2$ exists (pointing to the third character).
• Result is the string "5".

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Question 8

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Slicing: Slicing a string returns a new string containing the specified range.

Procedure

• "555"[:2] returns the substring from start to index $1$ (exclusive of $2$).
• Result is "55".
• Type is str.

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Question 9

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

• Same as Question 6: int is not subscriptable.

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Question 10

• int
• float
• str
• bool
• Invalid Expression (raises an error)

Abstract Solution (Strategy)

1. Index Type: String indices must be integers or slices, not strings.

Procedure

• ["2"] uses a string literal as an index.
• Python raises TypeError: string indices must be integers.
• Note: The original prompt had an extra quote typo "555""['2']", but the core issue is the string index.

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Question 11

• int
• float
• str
• bool
• Raises an error

Abstract Solution (Strategy)

1. Explicit Type Casting: float(2) converts the integer $2$ to $2.0$.
2. Arithmetic with Float: Any operation involving a float results in a float.

Procedure

• 5 + 2.0 = 7.0.
• Type is float.

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Question 12

• int
• float
• str
• bool
• Raises an error

Abstract Solution (Strategy)

• int(5.0) \to 5 (int)
• float("2") \to 2.0 (float)
• 5 + 2.0 = 7.0 (float)

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Question 13

• int
• float
• str
• bool
• Raises an error

Abstract Solution (Strategy)

1. String Concatenation: The + operator between two strings performs concatenation.

Procedure

• "5" + "2.0" evaluates to "52.0".
• Type is str.

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Question 14

python
Run Inline
3 + 4 * 5 // 2

• 3 + (4 * (5 // 2))
• 3 + ((4 * 5) // 2)
• (3 + 4) * (5 // 2)
• ((3 + 4) * 5) // 2

Abstract Solution (Strategy)

1. Operator Precedence: In Python, * and // have higher precedence than +.
2. Associativity: * and // have the same precedence and associate from left to right. ^operator-precedence-rule

Procedure

• Higher precedence first: 4 * 5 // 2.
• Left-to-right: (4 * 5) // 2.
• Finally addition: 3 + ((4 * 5) // 2).

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Question 15

python
Run Inline
10 // 2 * 5 ** 2

• ((10 // 2) * 5) ** 2
• (10 // 2) * (5 ** 2)
• 10 // ((2 * 5) ** 2)
• (10 // (2 * 5)) ** 2

Abstract Solution (Strategy)

1. Precedence Hierarchy:
   • ** (Exponentiation) - Highest
   • //, * (Multiplication/Division)
   • +, -
2. Evaluation: Evaluate ** first, then evaluate // and * from left to right. ^math-precedence-hierarchy

Procedure

• 5 ** 2 evaluates first.
• 10 // 2 then the result multiplied by $(5^2)$.
• Grouping: (10 // 2) * (5 ** 2).

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Question 16

python
Run Inline
(1 + 2) * (3 + 4)

• (1 + (2 * (3 + 4)))
• (1 + 2) * 3 + 4
• ((1 + 2) * (3 + 4))
• 1 + (2 * 3) + 4

Abstract Solution (Strategy)

• Parantheses already explicitly define the order. Outer parantheses are redundant but equivalent.

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Question 17

python
Run Inline
4 + 3 > 2 * 1

• (4 + 3) > (2 * 1)
• 4 + (3 > (2 * 1))
• (4 + 3 > 2) * 1
• 4 + (3 > 2) * 1

Abstract Solution (Strategy)

1. Precedence: Arithmetic (+, *) has higher precedence than Comparison (>).

Procedure

• Evaluate 4 + 3 and 2 * 1 before comparing.
• Equivalent to (4 + 3) > (2 * 1).

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Question 18

python
Run Inline
a and not b or not c

• (a and (not b)) or (not c)
• (a and not b) or (not c)
• a and (not (b or not c))
• a and ((not b) or (not c))

Abstract Solution (Strategy)

1. Logical Precedence:
   • not (Highest)
   • and
   • or (Lowest) ^logical-precedence-rule

Procedure

• not b and not c are evaluated first.
• Then a and (not b).
• Finally the or with (not c).

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Question 19

python
Run Inline
0 ** 1 ** 2 ** 3 ** 2

• (((0 ** 1) ** 2) ** 3) ** 2
• (0 ** (((1 ** 2) ** 3) ** 2))
• 0 ** (1 ** (2 ** (3 ** 2)))
• (0 ** ((1 ** 2) ** (3 ** 2)))

Abstract Solution (Strategy)

1. Right-Associativity: The exponentiation operator ** is right-associative in Python, meaning it evaluates from right to left.

Procedure

• $x ** y ** z$ is $x ** (y ** z)$.
• Here: 0 ** (1 ** (2 ** (3 ** 2))).

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Question 20

• print is a keyword.
• print can be used to display any data type.
• print at least requires one value.
• print prints a newline character at the end of the line.

Abstract Solution (Strategy)

1. Identify Function Type: print is a built-in function, not a keyword.
2. Utility: It converts arguments to their string representations.
3. Defaults: The default end parameter is \n.
4. Empty Print: Calling print() outputs a single newline and is valid.

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Question 21

• Output type can be passed to input as input(type) to get output in the required type.
• input accepts at most one argument.
• input is a built-in function.
• input can only be used in Python scripts and not in REPL/Notebook.

Abstract Solution (Strategy)

1. Signature: input(prompt=None) - only takes one optional string argument.
2. Type: Always returns a str. One must explicitly wrap it (e.g., int(input())).
3. Nature: It is a built-in function globally available.

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Question 22

• Line 1: a = 5
• Line 2: a = 5 - 1 = 4
• Line 3: a = 4 * 3 = 12

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Question 23

• Line 1: a = 14
• Line 2: a = 13
• Line 3: a = 39
• Line 4: a = 39 + 4 = 43

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Question 24

• Line 1: a = 23
• Line 2: a = 22
• Line 3: a = 66
• Line 4: a = 70
• Line 5: a = 70 // 2 = 35

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Question 25

• Line 1: a = 4
• Line 2: a = 4 + 3 = 7
• Line 3: a = 7 - 2 = 5

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Question 26

• Line 1: a = 13
• Line 2: a = 16
• Line 3: a = 14
• Line 4: a = 14 * 5 = 70

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Question 27

• Line 1: a = 8
• Line 2: a = 11
• Line 3: a = 9
• Line 4: a = 45
• Line 5: a = 45 // 2 = 22

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Question 28

python
Run Inline
word = '138412345678901938'

• Indices of '123456789' in the string:
  • 1: index 0
  • 3: index 1
  • 8: index 2
  • 4: index 3
  • 1: index 4
  • 2: index 5
  • ...
  • 9: index 12
• The sequence '123456789' starts at index 4 and ends at index 12.
• Slicing [a:b] is inclusive of a, exclusive of b.
• So a = 4, b = 13.

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Question 29

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Question 30

• Line 1: not E
• Line 2: not not E ($E$)
• Line 3: not E
• Line $n$ is $E$ if $n$ is even, and not E if $n$ is odd.
• Line 500 is even $\implies$ it evaluates to $E$.
• Since Line 500 is False, $E = \text{False}$.

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