How many days did sales go up on the day before

pandas · from shift, diff and change over time

.shift().diff().pct_change()grouped shiftleakagecumsum

Putting the kettle on…

Starting up…

Exercise 4

How many days did sales go up on the day before? Return the count.

your answer
stuck? the lesson behind it
shift, diff and change over time
Slide the column down a row, and every “compared to last time” question falls out.