Question

What if in the rename function we pass a value for a row label that does not exist?

Answer 1

If we pass a row label that does not exist in the rename() function, then no change will occur and the DataFrame will remain the same. he rename() function only changes the labels that are already present in the DataFrame. It ignores the labels that do not exist.

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