Python Data Science Jobs & Interviews
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Your go-to hub for Python and Data Scienceβ€”featuring questions, answers, quizzes, and interview tips to sharpen your skills and boost your career in the data-driven world.

Admin: @Hussein_Sheikho
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⁉️ Interview question
What happens when you call `plt.plot()` without specifying a figure or axes, and then immediately call `plt.show()`?

The function `plt.plot()` automatically creates a new figure and axes if none exist, and `plt.show()` displays the current figure. However, if multiple plots are created without clearing the figure, they may overlap or appear in unexpected orders due to matplotlib's internal state management. This behavior can lead to confusion, especially when working with loops or subplots.

#️⃣ tags: #matplotlib #python #datavisualization #plotting #beginner #codingchallenge

By: @DataScienceQ πŸš€
⁉️ Interview question
How does `plt.subplot()` differ from `plt.subplots()` when creating a grid of plots?

`plt.subplot()` creates a single subplot in a grid by specifying row and column indices, requiring separate calls for each subplot. In contrast, `plt.subplots()` creates the entire grid at once, returning both the figure and an array of axes objects, making it more efficient for managing multiple subplots. However, using `plt.subplot()` can lead to overlapping or misaligned plots if not carefully managed, especially when adding elements like titles or labels.

#️⃣ tags: #matplotlib #python #plotting #subplots #datavisualization #beginner #codingchallenge

By: @DataScienceQ πŸš€
How can you use Seaborn to create a heatmap that visualizes the correlation matrix of a dataset, and what are the key steps involved in preprocessing the data and customizing the plot for better readability? Provide a detailed code example with explanations at an intermediate level, including handling missing values, selecting relevant columns, and adjusting the color palette and annotations.

import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

# Step 1: Load a sample dataset (e.g., tips from seaborn's built-in datasets)
df = sns.load_dataset('tips')

# Step 2: Select only numeric columns for correlation analysis
numeric_df = df.select_dtypes(include=[np.number])

# Step 3: Handle missing values (if any)
numeric_df = numeric_df.dropna()

# Step 4: Compute the correlation matrix
correlation_matrix = numeric_df.corr()

# Step 5: Create a heatmap using Seaborn
plt.figure(figsize=(10, 8))
sns.heatmap(correlation_matrix, annot=True, cmap='coolwarm', center=0, linewidths=.5, fmt='.2f')
plt.title('Correlation Heatmap of Numeric Features in Tips Dataset')
plt.tight_layout()
plt.show()


Explanation:
- Step 1: We load a built-in dataset from Seaborn to work with.
- Step 2: Only numeric columns are selected because correlation is computed between numerical variables.
- Step 3: Missing values are removed to avoid errors during computation.
- Step 4: The corr() method computes pairwise correlations between columns.
- Step 5: sns.heatmap() creates a visual representation where colors represent correlation strength, annot=True adds the actual correlation coefficients, cmap='coolwarm' uses a diverging color scheme, and fmt='.2f' formats numbers to two decimal places.

#Seaborn #DataVisualization #Heatmap #Python #Pandas #CorrelationMatrix #IntermediateProgramming

By: @DataScienceQ πŸš€
🧠 Quiz: Which submodule of Matplotlib is commonly imported with the alias plt to create plots and visualizations?

A) matplotlib.animation
B) matplotlib.pyplot
C) matplotlib.widgets
D) matplotlib.cm

βœ… Correct answer: B

Explanation: matplotlib.pyplot is the most widely used module in Matplotlib, providing a convenient, MATLAB-like interface for creating a variety of plots and charts. It's standard practice to import it as import matplotlib.pyplot as plt.

#Matplotlib #Python #DataVisualization

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By: @DataScienceQ ✨
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