Purely label-location based indexer for selection by label.
.loc is primarily label based, but may also be used with a boolean array.
Allowed inputs are:
- A single label, e.g. 5 or 'a', (note that 5 is interpreted as a label of the index, and never as an integer position along the index).
- A list or array of labels, e.g. ['a', 'b', 'c'].
- A slice object with labels, e.g. 'a':'f' (note that contrary to usual python slices, both the start and the stop are included!).
- A boolean array.
.loc will raise a KeyError when the items are not found.
See more at Selection by Label