Numerical Computing with Python

How it works...

The indexing operator changes behavior based on what type of object is passed to it. The following pseudocode outlines how DataFrame indexing operator handles the object that it is passed:

>>> df[item]  # Where `df` is a DataFrame and item is some objectIf item is a string then    Find a column name that matches the item exactly    Raise KeyError if there is no match    Return the column as a SeriesIf item is a list of strings then    Raise KeyError if one or more strings in item don't match columns    Return a DataFrame with just the columns in the list

If item is a slice object then   Works with either integer or string slices   Raise KeyError if label from label slice is not in index   Return all ROWS that are selected by the sliceIf item is ...