Interview Questions and Answers

Ques 1. Explain the pivot_table function in Pandas.

pivot_table is used to create a spreadsheet-style pivot table as a DataFrame.

Example:

pd.pivot_table(df, values='value', index='index_column', columns='column_to_pivot')

Ques 2. Explain the concept of MultiIndex in Pandas.

MultiIndex is used to represent hierarchical index levels in a DataFrame.

Ques 3. Explain the use of the transform() function in Pandas.

transform() is used to perform group-specific computations and return a DataFrame with the same shape as the input.

Example:

df['normalized_column'] = df.groupby('group_column')['value_column'].transform(lambda x: (x - x.mean()) / x.std())

Ques 4. What is the purpose of the pipe() function in Pandas?

pipe() is used to apply a function to a DataFrame using method chaining.

Example:

df.pipe(my_function).dropna()

Ques 5. Explain the purpose of the stack() and unstack() functions in Pandas.

stack() is used to pivot the columns of a DataFrame to the rows. unstack() does the reverse operation.

Example:

df.stack()