Pure functions in Python

Questions 1 to 5 of 7

1. 1. Is within_limit pure? Answer true or false, with the reason. ``python LIMIT = 10 def within_limit(n): return n <= LIMIT ``

   True, because the function only compares two numbers and prints nothingFalse, because it reads the global name LIMIT, which is not a parameter and can be changed by other code
2. 2. Is this function pure? Answer true or false, with the reason. The function adds up a list of prices, prints the total with print, and then returns the total.

   False, because printing changes the outside world, which is a side effectTrue, because the returned total depends only on the list it was given
3. 3. What does this program print? ``python def sorted_copy(xs): copy = list(xs) copy.sort() return copy a = [3, 1, 2] b = sorted_copy(a) print(a, b) ``

   [1, 2, 3] [1, 2, 3][3, 1, 2] [3, 1, 2][3, 1, 2] [1, 2, 3][1, 2, 3] [3, 1, 2]
4. 4. What does this program print? (one line per output) ``python TAX_RATE = 0.18 def price_with_tax(price): return price * (1 + TAX_RATE) print(price_with_tax(50.0)) TAX_RATE = 0.05 print(price_with_tax(50.0)) ``

   59.0 and 59.059.0 and 52.559.0 and 50.059.0 and 55.0
5. 5. Which change makes within_limit pure?

   Pass the limit in as a parameter, such as within_limit(n, limit)Store the limit in a global name and reset it before each callPrint the limit before the comparisonRead the limit from a file on every call