A main difference to NumPy consists in usage of arbitrary indices.
>>> fruits = ['apples', 'oranges', 'cherries', 'pears']
>>> quantities = [20, 33, 52, 10]
>>> S = pd.Series(quantities, index=fruits)
>>> S
apples 20
oranges 33
cherries 52
pears 10
dtype: int64
>>>
Adding two series with the same index:
>>> S2 = pd.Series([17, 13, 31, 32], index=fruits)
>>> S + S2
apples 37
oranges 46
cherries 83
pears 42
dtype: int64
>>>