For the following code we are working with ndarray called “taxi”. We calculated “trip_mph” below which is originally not a part of “taxi”. But then in the line 2 we are only selecting rows for which trip_mph<100 in taxi. But trip_mph was not a part of taxi, so how does python knows which values to pull?
trip_mph = taxi[:,7] / (taxi[:,8] / 3600) cleaned_taxi = taxi[trip_mph < 100]