# Pavan Kumpatla # December 27, 2021 # I learned about global and local variable - scopes # I didn't have any trouble

# Compute the area of a square def square_area (side): # area is a local variable in square_area area = side ** 2 # side to the power of 2, stores return area # returns # Global scope square_area(2) # calls function # area is not within scope anymore and cannot be # accessed from this global scope print(area) # prints - error

# Compute the area of a square def square_area (side): # area is a local variable in square_area area = side ** 2 return area # Compute the volume of a cube def cube_volume (side): # cube volume = area of base X side volume = area * side # area is not defined within this scope # error since "area" is from another function return volume # returns # Global scope s = 2 # stores square_area(s) # area was deleted when the local scope of square_area was destroyed cube_volume(s) # calls

# Compute the area of a square def square_area (side): # area is a local variable in square_area # area does not conflict with the variable area in rectangle_area area = side ** 2 # stores the side, which is to the power of 2 print("square area =", area) # prints # Compute the area of a rectangle def rectangle_area (length, width): # area is a local variable in rectangle_area # area does not conflict with the variable area in square_area area = length * width # stores print("rectangle area =", area) # prints # Global scope square_area(2) # calls function rectangle_area(2, 3) # calls function

# [ ] Fix the program below so it displays the area of a square with a side = 2 # Compute the area of a square def square_area (side): # area is a local variable in square_area area = side ** 2 # stores the side to the power of 2 return area # returns # Global scope square_area(2) # calls # area is not within scope anymore and cannot be # accessed from this global scope print(square_area(2)) # prints

# [ ] Fix the program below so it displays the area of a square with side = 2 # and the volume of a cube with side = 2 # Compute the area of a square def square_area (side): # area is a local variable in square_area area = side ** 2 return area # Compute the volume of a cube def cube_volume (side): # cube volume = area of base X side area = side ** 2 volume = area * side # area is not defined within this scope return volume # Global scope s = 2 square_area(s) # area was deleted when the local scope of square_area was destroyed cube_volume(s)

# [ ] The program below converts US Dollars to Euros, British Pounds, and Japanese Yen # Complete the functions USD2EUR, USD2GBP, USD2JPY so they all return the correct value def USD2EUR(amount): """ Convert amount from US Dollars to Euros. Use 1 USD = 0.831467 EUR args: amount: US dollar amount (float) returns: value: the equivalent of amount in Euros (float) """ value = amount * 0.831467 # multiplies, stores return value # stores def USD2GBP(amount): """ Convert amount from US Dollars to British Pounds. Use 1 USD = 0.739472 GBP args: amount: US dollar amount (float) returns: value: the equivalent of amount in British Pounds (float) """ value = amount * 0.739472 # multiplies, stores return value # stores def USD2JPY(amount): """ Convert amount from US Dollars to Japanese Yen. Use 1 USD = 112.656 JPY args: amount: US dollar amount (float) returns: value: the equivalent of amount in Japanese Yen (float) """ value = amount * 112.656 # multiplies, stores return value # stores def main(): amount = float(input("Enter amount in USD: $")) # In Euros eur = USD2EUR(amount) # In British Pounds gbp = USD2GBP(amount) # In Japanese Yen jpy = USD2JPY(amount) print("${:.2f} USD = {:.2f} EUR, {:.2f} GBP, {:.2f} JPY".format(amount, eur, gbp, jpy)) if __name__ == '__main__': main()

# Compute the area of a square def square_area (side): # area is a local variable in square_area # area does not conflict with the variable area in rectangle_area or area_diff area = side ** 2 return area # Compute the area of a rectangle def rectangle_area (length, width): # area is a local variable in rectangle_area # area does not conflict with the variable area in square_aream or area_diff area = length * width return area # Compute the area difference between a square and a rectangle def area_diff (side, length, width): # square area area1 = square_area(side) # defines area in its local scope # stores function # rectangle area area2 = rectangle_area(length, width) # defines area in its local scope # stores function # area difference area = area2 - area1 # area is local in area_diff local scope # subtracts, stores return area # returns # Call the area_diff function print("Area difference = ", area_diff(2, 2, 3)) # prints, calls function

# [ ] The program below converts US Dollars to British Pounds. However, the conversion rate is unknown # Complete the functions USD2EUR, EUR2GBP, and USD2GBP so they all return the correct value # You should use USD2EUR and EUR2GBP in USD2GBP, do not try to find out the conversion rate def USD2EUR(amount): """ Convert amount from US Dollars to Euros. Use 1 USD = 0.831467 EUR args: amount: US dollar amount (float) returns: value: the equivalent of amount in Euros (float) """ value = amount * 0.831467 # multiplies return value # stores def EUR2GBP(amount): """ Convert amount from Euros to British Pounds. Use 1 EUR = 0.889358 GBP args: amount: Euros amount (float) returns: value: the equivalent of amount in GBP (float) """ value = amount * 0.889358 # multiplies return value # stores def USD2GBP(amount): """ Convert amount from US Dollars to British Pounds. The conversion rate is unknown, you have to use USD2EUR and EUR2GBP args: amount: US dollar amount (float) returns: value: the equivalent of amount in British Pounds (float) """ value2 = amount * 0.831467 # multiplies value = value2 * 0.889358 # multiplies return value # stores def main(): amount = float(input("Enter amount in USD: $")) # In British Pounds gbp = USD2GBP(amount) print("${:.2f} USD = {:.2f} GBP".format(amount, gbp)) if __name__ == '__main__': main()

# Global variable pi = 3.14 # stores # Compute the area of a circle def circle_area (radius): # pi is accessible from this local scope area = pi * radius ** 2 # stores return area # returns # Global scope a = circle_area(4) # calls function, stores print("circle area =", a) # prints

# Global variable vowels = 'AaEeIiOoUiYy' # stores # Count the number of vowels in a sentence def count_vowels(sentence): # vowels is accessible from this local scope count = 0 # stores for c in sentence: # for c in sentence if c in vowels: # if c is in vowels count = count + 1 # add 1 to count return count # returns # Global scope s = 'Monty Python' # stores print('Number of vowels in "{:s}" = {:d}'.format(s, count_vowels(s))) # prints, formats

# Global variable pi = 3.14 # stores # Compute the area of a circle def circle_area (radius): # Define pi as a global variable in this scope global pi # pi is now global pi = 3.14159265359 # More accurate pi area = pi * radius ** 2 # multiplies, stores return area # returns # Global scope print("pi =", pi) # prints a = circle_area(4) # calls function, store print("More accurate circle area =", a) # prints print("Updated pi =", pi) # Global variable pi changed in circle_area # prints

# String global variable planet = 'Mercury' # stores # function to change the current planet def planet_change(new_planet): # Define planet as a global variable in this scope global planet # planet is now global planet = new_planet # stores # Global scope print("Planet =", planet) # prints planet_change('Mars') # calls function print("Planet =", planet) # prints

# Global variable pi = 3.14 # stores # Compute the area of a circle def circle_area (radius): # Assigning a value to pi without (global) makes it a local variable pi = 3.14159265359 # more accurate pi # stores area = pi * radius ** 2 # multiplies, stores return area # returns # Global scope print("pi =", pi) # prints a = circle_area(4) # calls function, stores print("More accurate circle area =", a) # prints print("Unchanged pi =", pi) # Global pi didn't change # prints

# String global variable planet = 'Mercury' # stores # Function to change the current planet def planet_change(new_planet): # creates new function with parameter planet = new_planet # planet is a local variable # stores # Global scope print("Planet = ", planet) # prints planet_change('Mars') # calls function print("Planet = ", planet) # prints

# Global variable pi = 3.14 # Compute the area of a circle def circle_area (radius): # pi is accessible from this local scope area = pi * radius ** 2 return area # Global scope # pi is changed before it is used in circle_area pi = 0 a = circle_area(4) print("pi =", pi) print("Wrong circle area =", a)

# String global variable planet = 'Mercury' # stores # Function to change the current planet def planet_change(new_planet): # creates new function with parameter planet = new_planet # planet is a local variable # stores print("Planet = ", planet) # prints planet_change('Mars') # calls function print("Planet = ", planet) # Global variable (planet) did not change # prints planet = "Earth" # Changing global variable (planet) # reassigns print("Planet = ", planet) # prints

# [ ] The following program converts an amount from US Dollars to Indian Rupees using the XCHANGE_RATE variable # Complete the function USD2INR so it performs the conversion XCHANGE_RATE = 63.6856 # = 1 USD def USD2INR(amount): """ Convert amount from US Dollars to Indian Rupees. Use XCHANGE_RATE args: amount: US dollar amount (float) returns: value: the equivalent of amount in Indian Rupees (float) """ value = XCHANGE_RATE * amount # multiplies, stores return value # returns print("Current exchange rate $1 USD = {} INR".format(XCHANGE_RATE)) amount = 220 #USD inr = USD2INR(amount) print("${} = {}".format(amount, inr))

# [ ] The following program calculates the equivalent of $220 USD in Indian Rupees, # then updates the exchange rate and performs the conversion again # Complete the functions USD2INR and change_rate so they function according to the specifications below XCHANGE_RATE = 63.6856 # = 1 USD def USD2INR(amount): """ Convert amount from US Dollars to Indian Rupees. Use XCHANGE_RATE args: amount: US dollar amount (float) returns: value: the equivalent of amount in Indian Rupees (float) """ value = XCHANGE_RATE * amount # multiplies, stores return value # returns def change_rate(): """ Change the exchange rate to 63.6782 args: None returns: None """ global XCHANGE_RATE # XCHANGE_RATE is now global XCHANGE_RATE = 63.6782 # reassigns print("Current exchange rate $1 USD = {} INR".format(XCHANGE_RATE)) amount = 220 #USD inr = USD2INR(amount) print("${} = {}".format(amount, inr)) print() change_rate() print("After changing the exchange rate $1 USD = {} INR".format(XCHANGE_RATE)) inr = USD2INR(amount) print("${} = {}".format(amount, inr))

# [ ] In the following program, the function `flip()` is designed to reverse the order of the elements in NUMBERS # Fix the `UnboundLocalError` exception without changing the expression (NUMBERS = NUMBERS[-1:0:-1]) NUMBERS = [1, 2, 3, 4, 5, 6] # stores in list def flip(): # creates new function global NUMBERS # NUMBERS is now global NUMBERS = NUMBERS[-1::-1] # stores print("Before flipping, NUMBERS =", NUMBERS) # prints flip() # calls function print("After flipping, NUMBERS =", NUMBERS) # prints