First Difference Series

Problem

Return the first differences of a series as a list: [x[1] - x[0], x[2] - x[1], ...].

A series with fewer than two elements produces an empty list. This is the basic operation that removes a linear trend.

Hint

Loop over adjacent index pairs.

case 1

in: [[1,3,6,10]]

expected: [2,3,4]

case 2

in: [[5]]

expected: []

case 3

in: [[0,-2,0]]

expected: [-2,2]

case 4

in: [[2,2]]

expected: [0]

Starter codePython

def first_differences(series):
    # Your code here
    pass

4 test cases · run your code against them in the editor