Interview Questions and Answers

Ques 1. What is Pandas?

Pandas is an open-source data manipulation and analysis library for Python.

Ques 2. How to import Pandas?

You can import Pandas using the statement: import pandas as pd

Ques 3. What is a DataFrame?

A DataFrame is a two-dimensional, tabular data structure in Pandas.

Ques 4. How to create a DataFrame in Pandas?

You can create a DataFrame using the pd.DataFrame() constructor.

Example:

df = pd.DataFrame({'Column1': [1, 2, 3], 'Column2': ['A', 'B', 'C']})

Ques 5. How to select specific columns in a DataFrame?

You can select specific columns using double square brackets: df[['Column1', 'Column2']]

Ques 6. What is the purpose of the describe() function in Pandas?

describe() provides summary statistics of numeric columns in a DataFrame.

Example:

df.describe()

Ques 7. Explain the concept of broadcasting in Pandas.

Broadcasting allows operations between arrays of different shapes and sizes.

Example:

df['Column'] = df['Column'] * 2

Ques 8. Explain the purpose of the crosstab() function in Pandas.

crosstab() computes a cross-tabulation of two or more factors.

Example:

pd.crosstab(df['Factor1'], df['Factor2'])

Ques 9. How to handle categorical data in Pandas?

You can use the astype() method to convert a column to a categorical type: df['Category'] = df['Category'].astype('category')

Ques 10. Explain the use of the nunique() function in Pandas.

nunique() returns the number of unique elements in a column.

Example:

df['Column'].nunique()

Ques 11. What is the use of the nlargest() function in Pandas?

nlargest() returns the first n largest elements from a series or DataFrame.

Example:

df['Column'].nlargest(5)

Ques 12. How to convert a Pandas DataFrame to a NumPy array?

You can use the values attribute: df.values