20 Pandas Interview Questions

# Question Companies Difficulty Type Frequency
1 What is a DataFrame in Pandas? Amazon, Infosys Easy Theory Most frequent
2 Difference between Series and DataFrame. Google, TCS Easy Theory Most frequent
3 How to read CSV/Excel files in Pandas? Microsoft, Cognizant Easy Practical Most frequent
4 How to handle missing values (dropna, fillna)? Meta, Wipro Easy Both Most frequent
5 How do you check for null values in a DataFrame? Amazon, Capgemini Easy Practical Most frequent
6 Difference between loc and iloc. Google, Infosys Medium Theory + Practical Most frequent
7 How do you filter rows based on conditions? Microsoft, Cognizant Easy Practical Most frequent
8 How to merge/join DataFrames? Amazon, Wipro Medium Practical Most frequent
9 How to concatenate DataFrames? Meta, TCS Medium Practical Normal
10 How do you group data and use agg()? Google, Infosys Medium Both Most frequent
11 Difference between apply, map, and applymap. Amazon, Capgemini Medium Both Normal
12 How to create pivot tables in Pandas? Microsoft, Infosys Medium Practical Normal
13 How to change column data types? Google, TCS Easy Practical Normal
14 How do you sort data in Pandas? Amazon, Cognizant Easy Practical Most frequent
15 How to reset and set index? Meta, Wipro Easy Practical Normal
16 How to rename columns in Pandas? Google, Infosys Easy Practical Most frequent
17 Difference between iterrows() and itertuples(). Amazon, Microsoft Medium Theory + Practical Medium
18 How to remove duplicates in a DataFrame? Infosys, TCS Easy Practical Most frequent
19 How to export DataFrame to CSV/Excel? Google, Cognizant Easy Practical Normal
20 Explain vectorized operations in Pandas. Amazon, Wipro Medium Theory

20 NumPy Interview Questions

# Question Companies Difficulty Type Frequency
1 What is NumPy and why is it faster than lists? Google, Infosys Easy Theory Most frequent
2 How to create arrays (array, arange, linspace)? Amazon, TCS Easy Practical Most frequent
3 Difference between Python lists and NumPy arrays. Microsoft, Cognizant Easy Both Most frequent
4 How do you check shape and size of an array? Meta, Infosys Easy Practical Most frequent
5 How to reshape arrays (reshape, ravel)? Amazon, Capgemini Easy Practical Most frequent
6 How do you slice and index arrays? Google, Wipro Easy Practical Most frequent
7 Difference between shallow copy and deep copy in NumPy. Amazon, Infosys Medium Theory Normal
8 How to perform element-wise operations in NumPy? Microsoft, TCS Easy Practical Most frequent
9 What are broadcasting rules in NumPy? Meta, Capgemini Medium Theory Most frequent
10 How to compute statistics (mean, std, sum)? Amazon, Infosys Easy Practical Most frequent
11 How to handle NaN values in NumPy arrays? Google, Wipro Medium Practical Normal
12 What is the difference between flatten and ravel? Microsoft, Cognizant Medium Theory + Practical Normal
13 How do you concatenate and split arrays? Amazon, Infosys Easy Practical Most frequent
14 How do you perform dot product and matrix multiplication? Google, TCS Medium Practical Normal
15 How to generate random numbers in NumPy? Meta, Infosys Easy Practical Most frequent
16 What is vectorization in NumPy? Amazon, Microsoft Medium Theory Normal
17 Difference between np.array and np.asarray. Google, Capgemini Medium Theory Medium
18 What are structured arrays in NumPy? Infosys, TCS Hard Theory Rare
19 How do you use slicing with steps? Amazon, Wipro Easy Practical Most frequent
20 Explain NumPy memory layout (C vs F order). Microsoft, Meta Hard Theory Rare

20 Matplotlib Interview Questions

# Question Companies Difficulty Type Frequency
1 What is Matplotlib and why is it used? Google, Infosys Easy Theory Most frequent
2 How to plot a simple line chart? Amazon, TCS Easy Practical Most frequent
3 Difference between plot, scatter, and bar. Microsoft, Cognizant Easy Both Most frequent
4 How to set labels and titles in plots? Meta, Wipro Easy Practical Most frequent
5 How do you add a legend to a chart? Amazon, Infosys Easy Practical Most frequent
6 How to customize line styles and colors? Google, Capgemini Easy Practical Most frequent
7 How to create multiple subplots? Microsoft, Infosys Medium Practical Most frequent
8 How do you save a figure in Matplotlib? Amazon, Wipro Easy Practical Most frequent
9 How to adjust figure size in plots? Google, Cognizant Easy Practical Normal
10 How to add grid lines to plots? Infosys, TCS Easy Practical Normal
11 Difference between plt.show() and plt.savefig(). Meta, Amazon Easy Theory Normal
12 How to create histograms in Matplotlib? Google, Wipro Easy Practical Most frequent
13 How to create pie charts in Matplotlib? Microsoft, Infosys Easy Practical Normal
14 What are stacked bar charts and how to make them? Amazon, Capgemini Medium Practical Normal
15 How do you add text annotations? Google, Infosys Medium Practical Normal
16 How to control axis limits in a plot? Microsoft, Wipro Easy Practical Normal
17 What is the difference between ax.plot() and plt.plot()? Amazon, TCS Medium Theory Medium
18 How do you create filled area charts? Meta, Infosys Medium Practical Normal
19 How to customize ticks on axes? Google, Cognizant Medium Practical Normal
20 How to create 3D plots in Matplotlib? Microsoft, Amazon Hard Practical Rare

20 Seaborn Interview Questions

# Question Companies Difficulty Type Frequency
1 What is Seaborn and why is it used? Google, Infosys Easy Theory Most frequent
2 How do you load datasets in Seaborn? Amazon, TCS Easy Practical Most frequent
3 How to plot a scatter plot in Seaborn? Microsoft, Cognizant Easy Practical Most frequent
4 Difference between Seaborn and Matplotlib. Meta, Wipro Medium Theory Most frequent
5 How to create bar plots in Seaborn? Google, Infosys Easy Practical Most frequent
6 How to create count plots in Seaborn? Amazon, Capgemini Easy Practical Most frequent
7 How to create box plots in Seaborn? Microsoft, Infosys Easy Practical Most frequent
8 How to create violin plots in Seaborn? Meta, Wipro Medium Practical Normal
9 How to create pair plots in Seaborn? Google, Infosys Medium Practical Normal
10 What is a heatmap and how to plot it? Amazon, TCS Medium Practical Most frequent
11 How to customize color palettes in Seaborn? Microsoft, Cognizant Medium Practical Normal
12 How to show regression line in scatter plots? Meta, Infosys Medium Practical Normal
13 What are facet grids in Seaborn? Google, Wipro Medium Practical Medium
14 Difference between relplot, catplot, lmplot. Amazon, Infosys Medium Theory + Practical Medium
15 How do you rotate axis labels in Seaborn plots? Microsoft, TCS Easy Practical Normal
16 How to customize plot style (darkgrid, whitegrid)? Google, Cognizant Easy Practical Normal
17 How to annotate heatmaps in Seaborn? Amazon, Wipro Medium Practical Medium
18 What is hue in Seaborn plots? Meta, Infosys Easy Theory Most frequent
19 How do you handle large datasets in Seaborn? Google, Capgemini Medium Practical Medium
20 How to integrate Seaborn with Matplotlib? Amazon, Microsoft Medium Both Medium

20 Plotly Interview Questions

# Question Companies Difficulty Type Frequency
1 What is Plotly and how is it different from Matplotlib? Google, Infosys Medium Theory Most frequent
2 How do you create interactive line charts in Plotly? Amazon, TCS Easy Practical Most frequent
3 Difference between Plotly Express and Plotly Graph Objects. Microsoft, Cognizant Medium Theory + Practical Most frequent
4 How do you add hover tooltips to plots? Meta, Wipro Medium Practical Most frequent
5 How to plot scatter plots in Plotly? Google, Infosys Easy Practical Most frequent
6 How to create bar charts in Plotly? Amazon, Capgemini Easy Practical Most frequent
7 How to plot pie and donut charts? Microsoft, Infosys Easy Practical Normal
8 How to plot box plots and violin plots? Meta, Wipro Medium Practical Normal
9 How to plot heatmaps in Plotly? Google, Infosys Medium Practical Most frequent
10 How do you create subplots in Plotly? Amazon, TCS Medium Practical Medium
11 What are choropleth maps in Plotly? Microsoft, Cognizant Hard Practical Rare
12 How to plot 3D scatter plots in Plotly? Google, Infosys Hard Practical Medium
13 How to animate plots in Plotly? Amazon, Capgemini Hard Practical Medium
14 How to customize layouts in Plotly? Meta, Wipro Medium Practical Normal
15 How to change themes in Plotly? Google, Infosys Easy Practical Normal
16 How to add dropdowns/sliders in Plotly dashboards? Amazon, TCS Hard Practical Medium
17 How to integrate Plotly with Dash? Microsoft, Infosys Hard Practical Medium
18 How do you export Plotly figures to HTML/PDF? Meta, Capgemini Medium Practical Medium
19 How to add multiple traces to the same chart? Google, Wipro Medium Practical Most frequent
20 What are callbacks in Plotly Dash? Amazon, Microsoft Hard Theory + Practical Rare