02-02: Exercises — Variables and Data Types¶

Notes reference: 02-02: Variables and Data Types

Q1: Create and print variables¶

Create variables for a person: name (string), age (int), height in metres (float), and is_student (bool). Print all four.

Solution

name       = "Jahid"
age        = 28
height     = 1.75
is_student = True

print(name, age, height, is_student)
# Output: Jahid 28 1.75 True

Q2: Check data types¶

What does type() return for each of the following? Predict first, then verify.

type(42)
type(3.14)
type("Dhaka")
type(True)
type(None)

Solution

print(type(42))       # <class 'int'>
print(type(3.14))     # <class 'float'>
print(type("Dhaka"))  # <class 'str'>
print(type(True))     # <class 'bool'>
print(type(None))     # <class 'NoneType'>

Q3: Multiple assignment¶

Assign the values "New York", 10001, and True to variables city, zip_code, and is_capital in a single line.

Solution

city, zip_code, is_capital = "New York", 10001, True
print(city, zip_code, is_capital)

Q4: Same value, multiple variables¶

Assign the value 0 to three variables x, y, z in one line.

Solution

x = y = z = 0
print(x, y, z)  # 0 0 0

Q5: Spot the invalid variable names¶

Which of the following are invalid variable names? Explain each.

1st_place
total_score
my-variable
_hidden
class
user name

Solution

1st_place   → Invalid: cannot start with a digit
total_score → Valid
my-variable → Invalid: hyphen (-) is not allowed
_hidden     → Valid
class       → Invalid: reserved keyword
user name   → Invalid: spaces are not allowed

Q6: Dynamic typing¶

Assign an integer to a variable, print its type, then reassign a string to the same variable and print its type again.

Solution

data = 100
print(type(data))   # <class 'int'>

data = "one hundred"
print(type(data))   # <class 'str'>
# Python allows the same variable to hold different types

Q7: Swap two variables¶

Swap the values of a = "Dhaka" and b = "Chittagong" without using a third variable.

Solution

a = "Dhaka"
b = "Chittagong"

a, b = b, a

print(a)  # Chittagong
print(b)  # Dhaka

Q8: Type conversion basics¶

Convert the string "55" to an integer, the integer 7 to a float, and the float 9.8 to a string. Print the type of each result.

Solution

n = int("55")
print(type(n), n)      # <class 'int'> 55

f = float(7)
print(type(f), f)      # <class 'float'> 7.0

s = str(9.8)
print(type(s), s)      # <class 'str'> 9.8

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