Python Pandas Dataframe 如何根据另一列的长度重复一列中的值

Question

How do I repeat the values in one column multiple times based on the length of another column? Example: names = [Jack, Bob] and pets=[fish, cat, dog, bird]. I would like the dataframe to be:

    names   pets
0   Jack    fish
1   Jack    cat
2   Jack    dog
3   Jack    bird
4   Bob     fish
5   Bob     cat
6   Bob     dog
7   Bob     bird

How do I repeat the names (which will need to be filled in the names column) for every value in the pets column and then repeat the process for each name in names?

Answer 1

Using itertools.product :

import itertools
pd.DataFrame(itertools.product(names,pets), columns = ['names', 'pets'])

Answer 2

name=['jack','bob']
pets =['fish','cat','dog','bird']


index = pd.MultiIndex.from_product([name, pets], names = ["name", "pets"])

pd.DataFrame(index = index).reset_index()