Setting and renaming columns and indices#

Learning Objectives#

After working through this topic, you should be able to:

• Explain why the index is important

• Rename columns in a DataFrame

• Set single and MultiIndices

Materials#

Video:

Download the slides.

Quiz#

Using a meaningful index...

means that you will never have duplicate values in the index.means that we will not end up with MultiIndex objects.makes combining datasets safer.means that we are never going to use floats.

What will the output of the following code be?

>>> df.columns
Index(['a', 'b', 'c'], dtype='string')

>>> df = df.rename(columns={"b": "B", "x": "u"})
>>> df.columns

KeyError: 'a' and 'c' not found among dictionary keys {'b', 'x'}

Index(['a', 'B', 'c'], dtype='string')

KeyError: 'x'

Index(['a', 'B', 'c', 'u'], dtype='string')