Question

What would happen if the label or row index passed is not present in the DataFrame?

Answer 1

If the label or row index passed is not present in the DataFrame, then an error will occur if we try to access or modify it. The DataFrame can only perform operations on existing labels or indexes. If the label does not exist, Pandas cannot find it.

import pandas as pd
df = pd.DataFrame({'Marks': [85, 90, 78]}, index=['a', 'b', 'c'])
df_new = df.rename(index={'b': 'Beta', 'z': 'Omega'})
print(df_new)

Output:

	Marks
a	85
Beta	90
c	78