Looking up values in Series
Values in a Series object can be retrieved using the [] operator and passing either a single index label or a list of index labels. The following code retrieves the value associated with the index label 'a' of the s3 series defined earlier:
In [28]: # single item lookup s3['a'] Out[28]: 1
Accessing this Series using an integer value will perform a zero-based position lookup of the value:
In [29]: # lookup by position since the index is not an integer s3[1] Out[29]: 2
This is because pandas determines that the specified value is an integer and that the index is not an integer-based index. Given this, pandas decides to perform a lookup by position and not by index label.
To retrieve multiple items, you can pass a list of index labels via the [] operator. Instead of a single value, the result will be a new Series with both index labels and values, and data copied from the original Series.
In [30]: # multiple items s3[['a', 'c']] Out[30]...
