Python Week 1

🎯 The output type of the expression 5 + 2 in Python is int.

Let’s break it down step by step! 👇

Step-by-Step Explanation 🐍

1. Both operands are integers:
   • 5 is an integer (int)
   • 2 is also an integer (int)
2. Using the + operator:
   • The + operator adds two numbers.
   • When both numbers are integers, Python performs integer addition.
3. Result:
   • 5 + 2 evaluates to 7.
   • Since both operands are integers, the result is also an integer (int)[^1][^2][^3].

Practice It Yourself! 💻

Try this in your Python shell:

result = 5 + 2
print(result)           # Output: 7
print(type(result))     # Output: <class 'int'>

Why Not Other Types? 🤔

Quick Quiz! 📝

Q: What will be the type of the result for 5 + 2.0?

A) int

B) float

C) str

D) bool

Answer:

B) float

Explanation: When you add an integer and a float, Python automatically converts the result to a float.

Summary:

• 5 + 2 results in an int type output.
• You can always check the type using the type() function in Python.

Keep practicing! 🚀

✨ The output type of the expression 5 + 2.0 in Python is float.

Let’s see why, step by step! 🚀

Step-by-Step Explanation

1. Operands:
   • 5 is an integer (int)
   • 2.0 is a floating-point number (float)
2. Addition with Mixed Types:
   • When you add an int and a float, Python automatically converts the integer to a float (this is called implicit type conversion or type promotion)[^1].
3. Result:
   • The result of 5 + 2.0 is 7.0
   • The type of the result is float[^1].

Try It Yourself! 🧑‍💻

result = 5 + 2.0
print(result)           # Output: 7.0
print(type(result))     # Output: <class 'float'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the type of the result for 3.5 + 2?

A) int

B) float

C) str

D) bool

Answer:

B) float

Explanation: Adding a float and an int always results in a float in Python.

Summary:

• 5 + 2.0 results in a value of type float (7.0) in Python[^1].
• Python always promotes to the more “complex” type when mixing numbers: int → float → complex[^1].

Keep experimenting in the Python shell to see how types change! 🐍✨

🎉 The output type of the expression '5' + "2" in Python is str (string)!

Let’s see why, step by step! 🚦

Step-by-Step Explanation

1. Operands:
   • '5' is a string (because it’s inside single quotes).
   • "2" is also a string (because it’s inside double quotes).
2. The + Operator with Strings:
   • In Python, the + operator concatenates (joins) two strings together, not adds them as numbers[^1][^2].
   • So, '5' + "2" results in the string '52'.
3. Result Type:
   • The result is a new string: '52'
   • Its type is str.

Try It Yourself! 🧑‍💻

result = '5' + "2"
print(result)           # Output: 52
print(type(result))     # Output: <class 'str'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the type of the result for "Hello" + 'World'?

A) int

B) float

C) str

D) bool

Answer:

C) str

Explanation: Concatenating two strings always gives a string.

Summary:

• '5' + "2" produces a string: '52'
• Type: str (string)

Keep practicing and experimenting! 🚀

✅ The output type of the expression 5 == 2 in Python is bool (Boolean type).

Let’s understand step by step! 🐍

Step-by-Step Explanation

1. What does == do?
   • The == operator is a relational (comparison) operator in Python.
   • It checks if the value on the left (5) is equal to the value on the right (2).
2. What is the result of 5 == 2?
   • Since 5 is not equal to 2, the expression evaluates to False.
3. What is the type of the result?
   • The result of any comparison using relational operators (==, !=, <, >, <=, >=) is always of type bool in Python.
   • The possible values are True or False[1].

Try It Yourself! 💻

result = 5 == 2
print(result)           # Output: False
print(type(result))     # Output: <class 'bool'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the type of the result for "5" == 5?

A) int

B) float

C) str

D) bool

Answer:

D) bool

Explanation: Even though the values are not equal (string vs integer), the result of the comparison is False, and its type is bool.

Summary:

• 5 == 2 returns False
• Type: bool (Boolean)

Keep practicing and try more comparisons! 🚦✨

🚦 The output type of the expression '5 > 2' is str (string).

Let’s break it down step by step! 👇

Step-by-Step Explanation

1. Look at the quotes:
   • '5 > 2' is surrounded by single quotes.
   • In Python, anything inside quotes (single ' or double ") is treated as a string.
2. What is inside the string?
   • The content 5 > 2 is just text here, not an actual comparison.
   • Python does not evaluate the expression inside quotes. It just treats it as a sequence of characters.
3. So, what is the type?
   • The type is string (str).

Try It Yourself! 🧑‍💻

result = '5 > 2'
print(result)           # Output: 5 > 2
print(type(result))     # Output: <class 'str'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the type of the result for "Hello > World"?

A) int

B) float

C) str

D) bool

Answer:

C) str

Explanation: Anything inside quotes is a string, even if it looks like a comparison!

Summary:

• '5 > 2' is a string (str) because it’s inside quotes.
• If you want a comparison, write 5 > 2 (without quotes), which gives a bool.

Keep practicing and notice how quotes change the meaning in Python! 🐍✨

🌟 The output type of the expression "5" > "2" in Python is bool (Boolean)!

Let’s break it down step by step with clear explanation and a practice question! 👇

Step-by-Step Explanation

1. Both operands are strings:
   • "5" is a string (because it’s in double quotes)
   • "2" is also a string
2. The > operator between strings:
   • In Python, you can compare strings using relational operators like >, <, ==, etc.
   • The comparison is done lexicographically (like in a dictionary), comparing Unicode values of characters one by one[^1].
3. How does "5" > "2" work?
   • Python checks the Unicode value of '5' and '2'.
   • Since '5' comes after '2' in Unicode order, "5" > "2" evaluates to True.
4. What is the output type?
   • The result of any comparison operation is always of type bool (Boolean)[^1].

Try It Yourself! 🧑‍💻

result = "5" > "2"
print(result)           # Output: True
print(type(result))     # Output: <class 'bool'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the type of the result for "apple" < "banana"?

A) int

B) float

C) str

D) bool

Answer:

D) bool

Explanation: String comparisons return a Boolean value (True or False).

Summary:

• "5" > "2" results in a value of type bool (Boolean).
• The result is True because '5' is greater than '2' lexicographically.

Keep experimenting with different string comparisons! 🐍💡

✨ The output type of the expression 'True' or 'False' in Python is str (string).

Let’s break it down step by step! 🐍👇

Step-by-Step Explanation

1. Both operands are strings:
   • 'True' is a string (because it is inside single quotes).
   • 'False' is also a string.
2. The or operator with strings:
   • In Python, the or operator returns the first operand if it is “truthy” (not empty or zero); otherwise, it returns the second operand[^1].
   • Non-empty strings are always “truthy” in Python.
3. How does 'True' or 'False' evaluate?
   • Since 'True' is a non-empty string (truthy), Python returns 'True' and does not even evaluate the second operand (this is called short-circuit evaluation)[^1].
4. Type of the result:
   • The result is 'True', which is a string.
   • So, the output type is str.

Try It Yourself! 💻

result = 'True' or 'False'
print(result)           # Output: True
print(type(result))     # Output: <class 'str'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What is the type of the result for '' or 'Python'?

A) int

B) float

C) str

D) bool

Answer:

C) str

Explanation: The first operand is an empty string (falsy), so Python returns the second operand, which is a non-empty string. The type is str.

Summary:

• 'True' or 'False' returns 'True' (a string).
• Output type: str (string).

Keep experimenting with different types and the or operator! 🚀

🎯 The output type of the expression "555"[^1] in Python is str (string).

Let’s understand why, step by step! 👇

Step-by-Step Explanation

1. What is "555"?
   • It is a string containing three characters: '5', '5', '5'.
2. What does [^1] mean?
   • In Python, you can access individual characters in a string using indexing.
   • Indexing starts from 0, so:
     • "555" → '5'
     • "555"[^2] → '5'
     • "555"[^1] → '5'
3. What is the type of "555"[^1]?
   • When you access a single character from a string, the result is also a string of length 1, not an integer!¹²

Try It Yourself! 💻

result = "555"[^2]
print(result)           # Output: 5
print(type(result))     # Output: <class 'str'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What is the type of "hello"[^2]?

A) int

B) float

C) str

D) bool

Answer:

C) str

Explanation: Indexing a string always returns a string of length 1.

Summary:

• "555"[^1] returns '5' (as a string).
• Output type: str (string)¹².

🚨 The output type of the expression 555[::2] is: Invalid Expression (raises an error).

Let’s see why, step by step! 🐍

Step-by-Step Explanation

1. What is 555?
   • 555 is an integer (int), not a string or a list.
2. What does [::2] mean?
   • [::2] is slice notation, which is valid for sequences like strings, lists, or tuples.
   • You can use slicing on "555"[::2] or [1][2][::2], but not on integers.
3. What happens if you try 555[::2]?
   • Python will raise a TypeError because integers do not support slicing or subscripting.
4. What is the error message?

'int' object is not subscriptable

Try It Yourself! 💻

result = 555[::2]
# Output: TypeError: 'int' object is not subscriptable

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the output type of "555"[::2]?

• A) int
• B) float
• C) str
• D) bool
• E) Invalid Expression (raises an error)

Answer:

C) str

Explanation: Slicing a string returns a new string!

Summary:

• 555[::2] raises a TypeError because integers do not support slicing.
• Output type: Invalid Expression (raises an error) 🚫

Keep practicing and always check the type of object you are working with before using slicing! 🐍✨

🚨 The output type of the expression "555["2"]" is: Invalid Expression (raises an error).

Let’s see why, step by step! 👇

Step-by-Step Explanation

1. What is "555"?
   • It is a string containing three characters: '5', '5', '5'.
2. What does ["2"] mean?
   • In Python, you can use square brackets to access an element by its index in a string, like "555"[^1] (which gives '5').
   • The index must be an integer, not a string.
3. What happens with "555["2"]"?
   • Here, you are trying to use a string ("2") as the index, not an integer.
   • Python does not allow string indices for strings (unlike dictionaries, where keys can be strings).
4. What is the result?
   • Python raises a TypeError:

“string indices must be integers” - So, the expression is invalid and raises an error.

Try It Yourself! 💻

result = "555"["2"]
# Output: TypeError: string indices must be integers

Why Not Other Types? 🤔

Practice Question 📝

Q: What is the output type of "hello"[^2]?

• A) int
• B) float
• C) str
• D) bool
• E) Invalid Expression (raises an error)

Answer:

C) str

Explanation: Indexing a string with an integer returns a string of length 1.

Summary:

• "555["2"]" raises a TypeError because string indices must be integers, not strings.
• Output type: Invalid Expression (raises an error) 🚫

🌟 The output type of the expression print('True') is NoneType.

Let’s break it down step by step! 👇

Step-by-Step Explanation

1. What does print('True') do?
   • The print() function in Python displays the given argument(s) to the console.
   • In this case, it prints the string 'True' to the screen.
2. What does print() return?
   • The print() function does not return any value that you can use in your code.
   • Technically, it returns a special value called None.
3. What is the type of None?
   • The type of None is NoneType in Python.
4. Demonstration in Python:

result = print('True')   # This prints 'True' to the console
print(result)            # This prints: None
print(type(result))      # This prints: <class 'NoneType'>

• When you assign the result of print('True') to a variable, that variable will have the value None, and its type will be NoneType[^1].

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the output type of the expression x = print("Hello")?

• A) int
• B) float
• C) str
• D) bool
• E) NoneType

Answer:

E) NoneType

Explanation: The print() function always returns None, no matter what you print!

Summary:

• The output type of print('True') is NoneType because print() returns None[^1].

Keep experimenting with functions and their return types in Python! 🐍✨

🚨 The output type of the expression int("5.0") + float(2) is: Raises an error.

Let’s see why, step by step! 👇

Step-by-Step Explanation

1. int("5.0")
   • The int() function tries to convert its argument to an integer.
   • But: "5.0" is a string representation of a float, not an integer.
   • int("5.0") will raise a ValueError because Python expects a string that looks like an integer (e.g., "5"), not a float with a decimal point.

ValueError: invalid literal for int() with base 10: '5.0'[^1]

2. float(2)
   • This part is fine: float(2) gives 2.0 (a float).
3. The addition is never reached
   • Because the error happens at int("5.0"), the addition is never performed.

Try It Yourself! 💻

result = int("5.0") + float(2)
# Output: ValueError: invalid literal for int() with base 10: '5.0'

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the output type of the expression int("5") + float(2)?

• A) int
• B) float
• C) str
• D) bool
• E) Raises an error

Answer:

B) float

Explanation: int("5") gives 5, float(2) gives 2.0, and 5 + 2.0 results in 7.0 (a float).

Summary:

• int("5.0") + float(2) raises a ValueError because "5.0" is not a valid integer string for int()[^1].

🎉 The output type of the expression str(5) + str(2.0) is str (string)!

Let’s understand this step by step with a simple explanation and practice! 👇

Step-by-Step Explanation

1. What does str(5) do?
   • Converts the integer 5 to the string "5".
2. What does str(2.0) do?
   • Converts the float 2.0 to the string "2.0".
3. What does the + operator do with strings?
   • When used with strings, + concatenates (joins) them together, not adds them as numbers[^1].
4. What is the result of str(5) + str(2.0)?
   • It joins "5" and "2.0" to get "52.0", which is a string.
5. Type of the result:
   • The output is "52.0", and its type is str (string)[^1].

Try It Yourself! 🧑‍💻

result = str(5) + str(2.0)
print(result)           # Output: 52.0
print(type(result))     # Output: <class 'str'>

Why Not Other Types? 🤔

Practice Question 📝

Q: What will be the result and type of str(3) + str(4.5)?

• A) "34.5", str
• B) 7.5, float
• C) 7, int
• D) Raises an error

Answer:

A) "34.5", str

Explanation: Both are converted to strings and concatenated.

Summary:

• str(5) + str(2.0) results in "52.0"
• Output type: str (string)[^1]

Keep practicing string conversions and concatenations! 🚀

Let’s analyze which expressions are equivalent to the original:

5 * 6 + 3 / 1

Step-by-Step Calculation

• Multiplication and division have higher precedence than addition.
• So, Python evaluates as: $ (5 \times 6) + (3 \div 1) = 30 + 3 = 33.0 $

Let’s check each option:

Final Answer

The following expressions are equivalent to 5 * 6 + 3 / 1:

• (5 + 6) * 3 / 1
• (5 * 6 + 3) / 1
• (5 * 6) + (3 / 1)

Only the first option, 5 * (6 + (3 / 1)), is not equivalent because it changes the order of operations and gives a different result.

📝 Practice Question

Q: Which of the following is equivalent to 8 + 4 * 2?

• A) (8 + 4) * 2
• B) 8 + (4 * 2)
• C) (8 + 4 * 2)
• D) Both B and C

Answer:

D) Both B and C

Explanation: Multiplication happens before addition, so both B and C give 8 + 8 = 16. Option A gives 24.

Keep practicing! If you want to see the step-by-step for any other expression, just ask! 😃

Let’s evaluate which expressions are equivalent to:

(1 + 2) * (3 + 4)

Step-by-Step Calculation

• First, calculate inside the parentheses:
  • $1 + 2 = 3$
  • $3 + 4 = 7$
• Then multiply:
  • $3 \times 7 = 21$

Let’s check each option using the actual values (from the code execution):

Correct Answer

Only this expression is equivalent:

• ((1 + 2) * (3 + 4))

📝 Practice Question

What is equivalent to (2 + 3) * (4 + 1)?

• A) 2 + 3 * 4 + 1
• B) (2 + 3) * (4 + 1)
• C) 2 + (3 * (4 + 1))
• D) ((2 + 3) * 4) + 1

Answer:

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

Explanation: Only option B preserves the original grouping and order of operations.

Keep practicing! If you want to check more, just ask! 😃

Let’s analyze the original expression:

a == b > c

How Python Evaluates a == b > c

• Chained comparisons: Python allows chaining of comparison operators. a == b > c is equivalent to:

(a == b) and (b > c)

- Both comparisons must be true for the whole expression to be true.
- This is **not** the same as evaluating `(a == b)` first and then comparing the result to `c`.

Let’s check each option:

Correct Answer

The only equivalent expression is:

• (a == b) and (b > c)

📝 Practice Question

Which of the following is equivalent to x < y <= z?

• A) (x < y) and (y <= z)
• B) x < (y <= z)
• C) (x < y) or (y <= z)
• D) ((x < y) <= z)

Answer:

A) (x < y) and (y <= z)

Explanation: Python’s chained comparisons work like a logical and of each pair in the chain.

Keep practicing! If you want to see how Python evaluates other chained comparisons, just ask! 🐍✨

Let’s break down the original expression:

not (a or b) and c

Step-by-Step Evaluation

• Parentheses first: Evaluate (a or b)
• Apply not: not (a or b)
• Apply and c: [result above] and c

This is not the same as distributing not or changing the order of operations.

Now, let’s check each option:

Correct Answer

The only equivalent expression is:

• (not (a or b)) and c

📝 Practice Question

Which of the following is equivalent to not (x and y) or z?

• A) not x and y or z
• B) (not (x and y)) or z
• C) not x and (y or z)
• D) not (x and (y or z))

Answer:

B) (not (x and y)) or z

Explanation: Parentheses ensure the correct order of evaluation and logic.

Tip: Always use parentheses to make your logic clear and to avoid mistakes with operator precedence in Python![^1]

Let’s analyze the original expression:

not a or not b and c

Step-by-Step Evaluation

• Operator precedence:
  • not has higher precedence than and, which has higher precedence than or.
  • So, Python evaluates as: $ (not\ a) $ or $ ((not\ b)\ and\ c) $
• This is not the same as distributing not or changing grouping!

Let’s check each option:

Correct Answer

The only equivalent expression is:

• (not a) or ((not b) and c)

📝 Practice Question

Which of the following is equivalent to not x or not y and z?

• A) (not x) or ((not y) and z)
• B) not (x or (not y) and z)
• C) (not x) or (not (y and z))
• D) ((not x) or (not y)) and z

Answer:

A) (not x) or ((not y) and z)

Explanation: Operator precedence in Python means not is applied first, then and, then or.

Keep practicing with logical expressions and try using parentheses to clarify precedence! 🐍✨

Let’s break down how Python parenthesizes the expression:

not False or True and False

Step-by-Step: Python Operator Precedence

Python’s logical operator precedence is:

1. not (highest)
2. and
3. or (lowest)[^1][^2]

So, Python interprets the expression as:

1. not False is evaluated first → True
2. True and False is evaluated next → False
3. not False or (True and False) → True or False
4. True or False → True

So, the parenthesized version is:

(not False) or (True and False)

Let’s check the options:

📝 Practice Question

How does Python parenthesize: not True and False or True?

• A) ((not True) and False) or True
• B) not (True and (False or True))
• C) not (True and False) or True
• D) (not True) and (False or True)

Answer:

A) ((not True) and False) or True

Explanation: not first, then and, then or.

Summary:

• Python parenthesizes not False or True and False as (not False) or (True and False)[^1][^2].

Let’s review each statement about print in Python:

1️⃣ print is a built-in function.

✅ Correct!

• In Python 3, print is a built-in function, not a statement[^1].

2️⃣ In a python REPL/Notebook print("hi") will give same output as just “hi”.

❌ Incorrect!

• In the REPL or notebook, typing "hi" (just the string) will display 'hi' as the output (the string representation), but print("hi") will display hi as plain text.
• Example:
  • Typing "hi" ➡️ Output: 'hi'
  • Typing print("hi") ➡️ Output: hi
• So, the outputs are not exactly the same[^2].

3️⃣ print prints new line character at the end of the line.

✅ Correct!

• By default, print adds a newline character (\n) at the end of its output unless you specify otherwise with the end parameter[^1].

4️⃣ print can be used to display any data type.

✅ Correct!

• You can use print to display strings, numbers, lists, dictionaries, and any other data type. Python will automatically convert the object to a string for display[^1].

✔️ Summary Table

📝 Practice Question

Which of the following will print Hello without quotes in a Python REPL?

• A) "Hello"
• B) print("Hello")
• C) 'Hello'
• D) Both A and C

Answer:

B) print("Hello")

Explanation: Only print("Hello") prints the string as plain text, the others show the string with quotes.

If you want more details or examples, let me know! 😊

Let’s analyze each statement about input in Python:

1️⃣ input accepts at most one argument.

✅ Correct!

• The input function can take zero or one argument (the prompt string).
• Example: input() or input("Enter your name: ")
• Passing more than one argument will raise a TypeError.[^1][^2]

2️⃣ Output type can be passed to input as input(type) to get output in the required type.

❌ Incorrect!

• input(type) will just display type as the prompt, not convert the result.
• input always returns a string.
• To convert the input, you must use a constructor like int(input()) or float(input()) after calling input.[^2][^3]

3️⃣ input can be only used in python scripts and not in REPL/Notebook.

❌ Incorrect!

• input works in both Python scripts and in the Python REPL or Notebook environments.[^1][^2]
• You can use input() anywhere Python code is executed interactively.

4️⃣ Output type of input is always str

✅ Correct!

• The return value of input() is always a string (str), regardless of what the user types.[^2][^3]
• If you want a different type, you must convert the result.

✔️ Summary Table

📝 Practice Question

What is the output type of the following code?

x = input("Enter a number: ")
print(type(x))

• A) int
• B) float
• C) str
• D) bool

Answer:

C) str

Explanation: input() always returns a string, even if the user types a number!

If you want to convert the input to a number, use int(input(...)) or float(input(...)) after getting the input! 🎉

Let’s break down the task and options:

Task Recap

• Input: Two names (strings), one per line.
• Output: Print True if the first name comes before the second in alphabetical order, else False.

How Python compares strings:

• The < operator checks if the first string comes before the second in dictionary (lexicographical) order[^1].

Test Example

• Input:

sachin
rohit

Output:

False

Because “sachin” comes after “rohit”.

Let’s check each option:

Correct Implementations

• Option 1
• Option 3
• Option 5

All these use < to compare the first input with the second, which matches the required logic.

📝 Practice Question

Write a program to check if the first city name comes before the second city name alphabetically. Sample Input:

Mumbai
Delhi

Sample Output:

False

Solution:

city1 = input()
city2 = input()
print(city1 < city2)

Summary:

• Correct options:
  • name1 = input(); name2 = input(); print(name1 < name2)
  • print(input() < input())
  • name1 = input(); name2 = input(); result = name1 < name2; print(result)

Keep practicing string comparisons! 🚀

The type of the expression

(1 > 0) and (-1 < 0) and (1 == 1)

is bool.

Step-by-Step Explanation 🐍

• 1 > 0 evaluates to True (bool)
• -1 < 0 evaluates to True (bool)
• 1 == 1 evaluates to True (bool)
• All three are combined with the and operator, which returns a Boolean value (True or False).
• The type of the entire expression is bool (Boolean), not the value True or False, and not a string.

You can confirm this in Python:

result = (1 > 0) and (-1 < 0) and (1 == 1)
print(type(result))  # Output: <class 'bool'>

Practice Question 🎯

What is the type of the expression (5 != 3) or (2 > 7)?

• A) int
• B) bool
• C) str
• D) True

Answer:

B) bool

Explanation: Logical operations always return a Boolean value (True or False), and its type is bool.

So, the correct answer is: bool