Renaming columns in Data Analysis Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of renaming columns in a DataFrame?

Renaming columns helps make the data easier to understand and work with by giving columns clear and meaningful names.

beginner

How do you rename a single column in a pandas DataFrame?

Use the rename() method with a dictionary mapping old column name to new name, like df.rename(columns={'old_name': 'new_name'}, inplace=True).

beginner

What does the inplace=True argument do when renaming columns?

It changes the original DataFrame directly without needing to assign the result to a new variable.

beginner

Can you rename multiple columns at once? How?

Yes, by passing a dictionary with multiple old-to-new name pairs to rename(columns={...}).

intermediate

What happens if you rename a column that does not exist in the DataFrame?

Nothing changes for that name; pandas ignores keys in the dictionary that are not found in the DataFrame columns.

Which pandas method is used to rename columns in a DataFrame?

A rename()

B change_columns()

C set_columns()

D update_columns()

The correct method to rename columns is rename().

What argument do you pass to rename() to specify new column names?

A index

B labels

C names

D columns

You use the columns argument to rename columns.

What does setting inplace=True do when renaming columns?

A Modifies the original DataFrame directly

B Returns a new DataFrame without changing the original

C Deletes the columns

D Prints the new column names

inplace=True changes the original DataFrame directly.

If you want to rename columns 'A' to 'Alpha' and 'B' to 'Beta', how would you pass the dictionary?

A {'A': 'B', 'B': 'A'}

B {'Alpha': 'A', 'Beta': 'B'}

C {'A': 'Alpha', 'B': 'Beta'}

D {'Alpha': 'Beta', 'Beta': 'Alpha'}

The dictionary keys are old names and values are new names.

What happens if you try to rename a column that does not exist in the DataFrame?

A An error is raised

B Nothing changes for that column

C All columns are renamed

D The DataFrame is deleted

Pandas ignores keys not found in the DataFrame columns.

Explain how to rename columns in a pandas DataFrame and why it might be useful.

Think about making column names easier to understand.

Describe what happens when you rename multiple columns at once and include an example dictionary.

Use a dictionary with more than one pair.