Price changes month to month

arrays

Price changes month to month

Zillow Python Interview Question

Zillow's market reports show how a city's median home price changed from one month to the next.

Write a function percent_changes(prices) that takes a list of monthly median prices, oldest first, and returns a list with the percentage change from each month to the next, rounded to 1 decimal place. A list with fewer than two prices has no changes, so return an empty list.

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Example 1

Input

percent_changes([400000, 420000, 399000])

Output

[5, -5]

Example 2

Input

percent_changes([250000])

Output

[]

Explanation

In the first example, the price rose from 400,000 to 420,000, which is a 5.0% increase, and then fell to 399,000, which is a 5.0% drop. In the second example there is only one month, so there are no changes to report.

Submit also runs 3 hidden test cases that check edge cases.