A sensor logs temperature readings through the night. Write coldest(readings) that returns the lowest reading without using the built-in min function. Return None if there are no readings.
Examples
Input: readings = [3.5, -2.0, 7.1]
Output: -2.0
Input: readings = []
Output: None
Constraints
0 <= len(readings) <= 5000
Goals
- Find the smallest value with your own loop
- Return None when there is no data