Numerical Computing with Python

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One of the keys to using stack is to place all of the columns that you do not wish to transform in the index. The dataset in this recipe was initially read with the states in the index. Let's take a look at what would have happened if we did not read the states into the index:

>>> state_fruit2 = pd.read_csv('data/state_fruit2.csv')>>> state_fruit2

As the state names are not in the index, using stack on this DataFrame reshapes all values into one long Series of values:

>>> state_fruit2.stack()0  State       Texas Apple 12 Orange 10 Banana 40 1 State Arizona Apple 9 Orange 7 Banana 12 2 State Florida Apple 0 Orange 14 Banana 190 dtype: ...