Price list behind API
There is a list of around 100_000 prices in the range £0 to £100_000, expressed
in whole £, (no pence); and prices may be duplicated.
The API allows access to the maximum item price via
function get_max_price()
; and the number of items equal-to and between two
given price points via function get_prange_count(pricemin, pricemax)
.
Assume that for the purposes of testing, you have access to the actual number of priced items to split.
- Task
- Write functions to randomly generate around 100K prices and provide the
get_prange_count
andget_max_price
API calls. - Write functions to provide non-overlapping min and max price ranges that provide product counts where most are close to, but no more than, 5_000.
- Ensure that all priced items are covered by all the ranges of prices shown
- Show ascending price ranges and the number of items covered by each range.
- Show output from a sample run here.
Python <lang python>import random
- %%Sample price generation
price_list_size = random.choice(range(99_000, 101_000)) price_list = random.choices(range(100_000), k=price_list_size)
delta_price = 1 # Minimum difference between any two different prices.
- %% API
def get_prange_count(startp, endp):
return len([r for r in price_list if startp <= r <= endp])
def get_max_price():
return max(price_list)
- %% Solution
def get_5k(mn=0, mx=get_max_price(), num=5_000):
"Binary search for num items between mn and mx, adjusting mx" count = get_prange_count(mn, mx) delta_mx = (mx - mn) / 2 while count != num and delta_mx >= delta_price / 2: mx += -delta_mx if count > num else +delta_mx mx = mx // 1 # Floor count, delta_mx = get_prange_count(mn, mx), delta_mx / 2 return mx, count
def get_all_5k(mn=0, mx=get_max_price(), num=5_000):
"Get all non-overlapping ranges" partmax, partcount = get_5k(mn, mx, num) result = [(mn, partmax, partcount)] while partmax < mx: partmin = partmax + delta_price partmax, partcount = get_5k(partmin, mx, num) result.append((partmin, partmax, partcount)) return result
if __name__ == '__main__':
print(f"Using {price_list_size} random prices from 0 to {get_max_price()}") result = get_all_5k() print(f"Splits into {len(result)} bins of approx 5000 elements") for mn, mx, count in result: print(f" From {mn:8.1f} ... {mx:8.1f} with {count} items.")
if len(price_list) != sum(count for mn, mx, count in result): print("\nWhoops! Some items missing:")</lang>
- Output:
Using 99838 random prices from 0 to 99999 Splits into 20 bins of approx 5000 elements From 0.0 ... 4876.0 with 4999 items. From 4877.0 ... 9973.0 with 4997 items. From 9974.0 ... 14954.0 with 4999 items. From 14955.0 ... 20041.0 with 4997 items. From 20042.0 ... 25132.0 with 4999 items. From 25133.0 ... 30221.0 with 5000 items. From 30222.0 ... 35313.0 with 5000 items. From 35314.0 ... 40263.0 with 5000 items. From 40264.0 ... 45249.0 with 4997 items. From 45250.0 ... 50264.0 with 5000 items. From 50265.0 ... 55251.0 with 5000 items. From 55252.0 ... 60301.0 with 4997 items. From 60302.0 ... 65239.0 with 5000 items. From 65240.0 ... 70220.0 with 4998 items. From 70221.0 ... 75193.0 with 4999 items. From 75194.0 ... 80229.0 with 4996 items. From 80230.0 ... 85191.0 with 4997 items. From 85192.0 ... 90214.0 with 5000 items. From 90215.0 ... 95249.0 with 4999 items. From 95250.0 ... 104742.0 with 4864 items.