Pandas indexes allow efficient lookup of values. If indexes did not exist, a linear search across all of our data would be required. Indexes create optimized shortcuts to specific data items using a direct lookup instead of a search process.
To begin examining the value of indexes we will use the following DataFrame of 10000 random numbers:
Suppose we want to look up the value of the random number where key==10099 (I explicitly picked this value as it is the last row in the DataFrame). We can do this using a Boolean selection.
Conceptually, this is simple. But what if we want to do this repeatedly? This can be simulated ...