Alaska 1723337
Texas 695662
California 423967
Name: area, dtype: int64
population
California 38332521
Texas 26448193
New York 19651127
Name: population, dtype: int64
population/area
Alaska NaN
California 90.413926
New York NaN
Texas 38.018740
dtype: float64
area.index|population.index
/tmp/ipykernel_15930/3572280633.py:1: FutureWarning: Index.__or__ operating as a set operation is deprecated, in the future this will be a logical operation matching Series.__or__. Use index.union(other) instead.
area.index | population.index
Index(['Alaska', 'California', 'New York', 'Texas'], dtype='object')