# Practice Exercises for Functions
# Solve each of the practice exercises below.
# 1.Write a Python function miles_to_feet that takes a parameter miles and
# returns the number of feet in miles miles.
def miles_to_feet(miles):
feet = miles * 5280
return feet
print(miles_to_feet(2.5))
print('=====')
# 2.Write a Python function total_seconds that takes three parameters hours, minutes and seconds and
# returns the total number of seconds for hours hours, minutes minutes and seconds seconds.
def total_seconds(hours, minutes, seconds):
total = hours * 60 * 60 + minutes * 60 + seconds
return total
print(total_seconds(1, 5, 10))
print('=====')
# 3.Write a Python function rectangle_perimeter that takes two parameters width and height
# corresponding to the lengths of the sides of a rectangle and
# returns the perimeter of the rectangle in inches.
def rectangle_perimeter(width, height):
perimeter = (width + height) * 2
return perimeter
print(rectangle_perimeter(2.3, 2.2))
print('=====')
# 4.Write a Python function rectangle_area that takes two parameters width and height
# corresponding to the lengths of the sides of a rectangle and
# returns the area of the rectangle in square inches.
def rectangle_area(width, height):
area = width * height
return area
print(rectangle_area(2, 5))
print('=====')
# 5.Write a Python function circle_circumference that takes a single parameter radius
# corresponding to the radius of a circle in inches and
# returns the the circumference of a circle with radius radius in inches.
# Do not use π=3.14, instead use the math module to supply a higher-precision approximation to π.
import math
def circle_circumference(radius):
circumference = 2.0 * radius * math.pi
return circumference
print(circle_circumference(4.0))
print('=====')
# 6.Write a Python function circle_area that takes a single parameter radius
# corresponding to the radius of a circle in inches and
# returns the the area of a circle with radius radius in square inches.
# Do not use π=3.14, instead use the math module to supply a higher-precision approximation to π.
def circle_area(radius):
area = radius * radius * math.pi
return area
print(circle_area(4.0))
print('=====')
# 7.Write a Python function future_value that takes three parameters present_value, annual_rate and years and
# returns the future value of present_value dollars invested at annual_rate percent interest,
# compounded annually for years years.
def future_value(present_value, annual_rate, years):
value = present_value * pow(annual_rate + 1.0, years)
return value
print(future_value(1000000.0, 0.03, 10))
print('=====')
# 8.Write a Python function name_tag that takes as input the parameters first_name and last_name (strings) and
# returns a string of the form "My name is % %." where the percents are the strings first_name and last_name.
# Reference the test cases in the provided template for an exact description of
# the format of the returned string.
def name_tag(first_name, last_name):
form = "My name is %s %s." % (first_name, last_name)
return form
print(name_tag('Bob', 'Smith'))
print('=====')
# 9.Write a Python function name_and_age that takes as input the parameters name (a string) and age (a number) and
# returns a string of the form "% is % years old." where the percents are the string forms of name and age.
# Reference the test cases in the provided template for an exact description of
# the format of the returned string.
def name_and_age(name, age):
form = "%s is %d years old." % (name, age)
return form
print(name_and_age('John', 24))
print('=====')
# 10.Write a Python function point_distance that takes as the parameters x0, y0, x1 and y1, and
# returns the distance between the points (x0,y0) and (x1,y1).
def point_distance(x0, y0, x1, y1):
distance = math.sqrt((x0 - x1)**2 + (y0 - y1)**2)
return distance
print(point_distance(0, 0.5, -2.2, 3.5))
print('=====')
# 11.Challenge: Write a Python function triangle_area that takes the parameters x0, y0, x1,y1, x2, and y2, and
# returns the area of the triangle with vertices (x0,y0), (x1,y1) and (x2,y2).
# (Hint: use the function point_distance as a helper function and apply Heron's formula.)
def triangle_area(x0, y0, x1, y1, x2, y2):
side1 = point_distance(x0, y0, x1, y1)
side2 = point_distance(x1, y1, x2, y2)
side3 = point_distance(x2, y2, x0, y0)
area = heron_formula(side1, side2, side3)
return area
# 海伦公式
def heron_formula(side1, side2, side3):
p = (side1 + side2 + side3) / 2.0
area = math.sqrt(p * (p - side1) * (p - side2) * (p - side3))
return area
print(triangle_area(0, 0.5, -2.2, 3.5, -3, -2.5))
print('=====')
# 12.Challenge: Write a Python function print_digits that takes an integer number in the range [0,100),
# i.e., at least 0, but less than 100. It prints the message "The tens digit is %, and the ones digit is %.",
# where the percent signs should be replaced with the appropriate values.
# (Hint: Use the arithmetic operators for integer division // and remainder % to find the two digits.
# Note that this function should print the desired message, rather than returning it as a string.
def print_digits(number):
tens, ones = number // 10, number % 10
message = "The tens digit is %d, and the ones digit is %d." % (tens, ones)
print(message)
print_digits(49)
print('=====')
# 13.Challenge: Powerball is lottery game in which 6 numbers are drawn at random.
# Players can purchase a lottery ticket with a specific number combination and,
# if the number on the ticket matches the numbers generated in a random drawing,
# the player wins a massive jackpot. Write a Python function powerball that takes no arguments and
# prints the message "Today's numbers are %, %, %, %, and %. The Powerball number is %.".
# The first five numbers should be random integers in the range [1,60), i.e., at least 1,
# but less than 60. In reality, these five numbers must all be distinct, but for this problem,
# we will allow duplicates. The Powerball number is a random integer in the range [1,36),
# i.e., at least 1 but less than 36. Use the random module and the function random.randrange to
# generate the appropriate random numbers.Note that this function should print the desired message,
# rather than returning it as a string.
import random
def powerball():
ball1, ball2, ball3, ball4, ball5 = random.sample(range(1,60), 5)
ball6 = random.choice(range(1, 36))
message = "Today's numbers are %d, %d, %d, %d, and %d. The Powerball number is %d." % (ball1, ball2, ball3, ball4, ball5, ball6)
print(message)
powerball()
powerball()
print('=====')
