What will the following code return?
df.head()
df.head()
Anonymous Quiz
80%
First 5 rows
5%
First 15 rows
3%
Last 5 rows
12%
All rows
β€4π₯1
10 Simple Habits to Boost Your Data Science Skills π§ π
1) Practice data wrangling daily (Pandas, dplyr)
2) Work on small end-to-end projects (ETL, analysis, visualization)
3) Revisit and improve previous notebooks or scripts
4) Share findings in a clear, story-driven way
5) Follow data science blogs, newsletters, and researchers
6) Tackle weekly datasets or Kaggle competitions
7) Maintain a notebooks/journal with experiments and results
8) Version control your work (Git + GitHub)
9) Learn to communicate uncertainty (confidence intervals, p-values)
10) Stay curious about new tools (SQL, Python libs, ML basics)
π¬ React "β€οΈ" for more! π
1) Practice data wrangling daily (Pandas, dplyr)
2) Work on small end-to-end projects (ETL, analysis, visualization)
3) Revisit and improve previous notebooks or scripts
4) Share findings in a clear, story-driven way
5) Follow data science blogs, newsletters, and researchers
6) Tackle weekly datasets or Kaggle competitions
7) Maintain a notebooks/journal with experiments and results
8) Version control your work (Git + GitHub)
9) Learn to communicate uncertainty (confidence intervals, p-values)
10) Stay curious about new tools (SQL, Python libs, ML basics)
π¬ React "β€οΈ" for more! π
β€33π1π₯°1
π Python for Data Science β Complete Beginner Roadmap ππ
πΉ What is Data Science?
Data Science is about: Collecting data Cleaning it Analyzing it Finding insights Making predictions
π Example:
- Predict sales π
- Analyze customer behavior π
- Detect fraud π³
π§ Step-by-Step Roadmap
πΉ 1οΈβ£ Strengthen Python Basics
Focus on: Lists, dictionaries Loops & conditions Functions Basic file handling
π Because data is handled using these structures.
πΉ 2οΈβ£ Learn NumPy (Numerical Computing)
NumPy is used for: Fast calculations Working with arrays
import numpy as np
arr = np.array([1,2,3])
print(arr.mean())
π Used in: Machine learning Scientific computing
πΉ 3οΈβ£ Learn Pandas (Most Important π₯)
Pandas helps you: Read data (CSV, Excel) Clean data Analyze data
import pandas as pd
df = pd.read_csv("data.csv")
print(df.head())
π Must learn: head(), info() filtering groupby() merge()
πΉ 4οΈβ£ Data Visualization
Tools: matplotlib seaborn
import matplotlib.pyplot as plt
plt.plot([1,2,3],[10,20,30])
plt.show()
π Used to: Present insights Create reports Build dashboards
πΉ 5οΈβ£ Statistics Basics (Very Important)
Learn: Mean, Median, Mode Standard Deviation Probability basics
π Data science = math + logic + code
πΉ 6οΈβ£ Data Cleaning (Real-World Skill)
Real data is messy π
You should learn:
- Handling missing values
- Removing duplicates
- Fixing data types
df.dropna()
df.fillna(0)
πΉ 7οΈβ£ Intro to Machine Learning
Using scikit-learn:
from sklearn.linear_model import LinearRegression
Learn:
- Regression
- Classification
- Model training
πΉ 8οΈβ£ Real Projects (Most Important π)
Start building:
π‘ Project Ideas:
- Sales analysis dashboard
- IPL data analysis
- Netflix dataset insights
- Customer churn prediction
π§ Double Tap β€οΈ For More
πΉ What is Data Science?
Data Science is about: Collecting data Cleaning it Analyzing it Finding insights Making predictions
π Example:
- Predict sales π
- Analyze customer behavior π
- Detect fraud π³
π§ Step-by-Step Roadmap
πΉ 1οΈβ£ Strengthen Python Basics
Focus on: Lists, dictionaries Loops & conditions Functions Basic file handling
π Because data is handled using these structures.
πΉ 2οΈβ£ Learn NumPy (Numerical Computing)
NumPy is used for: Fast calculations Working with arrays
import numpy as np
arr = np.array([1,2,3])
print(arr.mean())
π Used in: Machine learning Scientific computing
πΉ 3οΈβ£ Learn Pandas (Most Important π₯)
Pandas helps you: Read data (CSV, Excel) Clean data Analyze data
import pandas as pd
df = pd.read_csv("data.csv")
print(df.head())
π Must learn: head(), info() filtering groupby() merge()
πΉ 4οΈβ£ Data Visualization
Tools: matplotlib seaborn
import matplotlib.pyplot as plt
plt.plot([1,2,3],[10,20,30])
plt.show()
π Used to: Present insights Create reports Build dashboards
πΉ 5οΈβ£ Statistics Basics (Very Important)
Learn: Mean, Median, Mode Standard Deviation Probability basics
π Data science = math + logic + code
πΉ 6οΈβ£ Data Cleaning (Real-World Skill)
Real data is messy π
You should learn:
- Handling missing values
- Removing duplicates
- Fixing data types
df.dropna()
df.fillna(0)
πΉ 7οΈβ£ Intro to Machine Learning
Using scikit-learn:
from sklearn.linear_model import LinearRegression
Learn:
- Regression
- Classification
- Model training
πΉ 8οΈβ£ Real Projects (Most Important π)
Start building:
π‘ Project Ideas:
- Sales analysis dashboard
- IPL data analysis
- Netflix dataset insights
- Customer churn prediction
π§ Double Tap β€οΈ For More
β€19π₯1π1
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β
Data Cleaning in Pandas ππ§Ή
π In real projects, 80% of the work = Data Cleaning
Because raw data is always messy π
πΉ 1. Why Data Cleaning?
Real-world data may have:
β Missing values
β Duplicate records
β Wrong formats
β Extra spaces
π Cleaning makes data usable for analysis & ML.
π₯ 2. Handling Missing Values
β Check Missing Values
df.isnull()
df.isnull().sum()
β Remove Missing Values
df.dropna()
β Fill Missing Values
df.fillna(0)
π Replace missing values with 0 or mean.
πΉ 3. Remove Duplicates
df.drop_duplicates()
πΉ 4. Rename Columns
df.rename(columns={"Name": "Full_Name"}, inplace=True)
πΉ 5. Change Data Types
df["Age"] = df["Age"].astype(int)
πΉ 6. Remove Extra Spaces
df["Name"] = df["Name"].str.strip()
πΉ 7. Replace Values
df["City"] = df["City"].replace("NY", "New York")
πΉ 8. Why This is Important?
β Clean data = better insights
β Clean data = better ML models
β Used in every real-world project
π― Todayβs Goal
β Handle missing values
β Remove duplicates
β Fix data types
β Clean text data
π Double Tap β€οΈ For More
π In real projects, 80% of the work = Data Cleaning
Because raw data is always messy π
πΉ 1. Why Data Cleaning?
Real-world data may have:
β Missing values
β Duplicate records
β Wrong formats
β Extra spaces
π Cleaning makes data usable for analysis & ML.
π₯ 2. Handling Missing Values
β Check Missing Values
df.isnull()
df.isnull().sum()
β Remove Missing Values
df.dropna()
β Fill Missing Values
df.fillna(0)
π Replace missing values with 0 or mean.
πΉ 3. Remove Duplicates
df.drop_duplicates()
πΉ 4. Rename Columns
df.rename(columns={"Name": "Full_Name"}, inplace=True)
πΉ 5. Change Data Types
df["Age"] = df["Age"].astype(int)
πΉ 6. Remove Extra Spaces
df["Name"] = df["Name"].str.strip()
πΉ 7. Replace Values
df["City"] = df["City"].replace("NY", "New York")
πΉ 8. Why This is Important?
β Clean data = better insights
β Clean data = better ML models
β Used in every real-world project
π― Todayβs Goal
β Handle missing values
β Remove duplicates
β Fix data types
β Clean text data
π Double Tap β€οΈ For More
β€25π5π₯1
Which library is used for basic plotting in Python?
Anonymous Quiz
8%
A) NumPy
7%
B) Pandas
82%
C) Matplotlib
4%
D) TensorFlow
β€6π1
Which function is used to display a plot?
Anonymous Quiz
7%
A) showplot()
6%
B) display()
61%
C) plt.show()
26%
D) plot.show()
β€6
What type of chart is best for showing trends over time?
Anonymous Quiz
14%
A) Bar chart
7%
B) Pie chart
61%
C) Line chart
17%
D) Histogram
β€2π1
Which library is used for advanced and attractive visualizations?
Anonymous Quiz
22%
A) Matplotlib
66%
B) Seaborn
7%
C) NumPy
5%
D) SciPy
β€2
What does a histogram show?
Anonymous Quiz
31%
A) Relationship between two variables
11%
B) Categories
56%
C) Distribution of data
2%
D) Exact values
β€6
β
Data Science Interview Prep Guide ππ§
Whether you're a fresher or career-switcher, hereβs how to prep step-by-step:
1οΈβ£ Understand the Role
Data scientists solve problems using data. Core responsibilities:
β’ Data cleaning & analysis
β’ Building predictive models
β’ Communicating insights
β’ Working with business/product teams
2οΈβ£ Core Skills Needed
βοΈ Python (NumPy, Pandas, Matplotlib, Scikit-learn)
βοΈ SQL
βοΈ Statistics & probability
βοΈ Machine Learning basics
βοΈ Data storytelling & visualization (Power BI / Tableau / Seaborn)
3οΈβ£ Key Interview Areas
A. Python & Coding
β’ Write code to clean and analyze data
β’ Solve logic problems (e.g., reverse a list, group data by key)
β’ List vs Dict vs DataFrame usage
B. Statistics & Probability
β’ Hypothesis testing
β’ p-values, confidence intervals
β’ Normal distribution, sampling
C. Machine Learning Concepts
β’ Supervised vs unsupervised learning
β’ Overfitting, regularization, cross-validation
β’ Algorithms: Linear Regression, Decision Trees, KNN, SVM
D. SQL
β’ Joins, GROUP BY, subqueries
β’ Window functions
β’ Data aggregation and filtering
E. Business & Communication
β’ Explain model results to non-tech stakeholders
β’ What metrics would you track for [business case]?
β’ Tell me about a time you used data to influence a decision
4οΈβ£ Build Your Portfolio
β Do projects like:
β’ E-commerce sales analysis
β’ Customer churn prediction
β’ Movie recommendation system
β Host on GitHub or Kaggle
β Add visual dashboards and insights
5οΈβ£ Practice Platforms
β’ LeetCode (SQL, Python)
β’ HackerRank
β’ StrataScratch (SQL case studies)
β’ Kaggle (competitions & notebooks)
π¬ Tap β€οΈ for more!
Whether you're a fresher or career-switcher, hereβs how to prep step-by-step:
1οΈβ£ Understand the Role
Data scientists solve problems using data. Core responsibilities:
β’ Data cleaning & analysis
β’ Building predictive models
β’ Communicating insights
β’ Working with business/product teams
2οΈβ£ Core Skills Needed
βοΈ Python (NumPy, Pandas, Matplotlib, Scikit-learn)
βοΈ SQL
βοΈ Statistics & probability
βοΈ Machine Learning basics
βοΈ Data storytelling & visualization (Power BI / Tableau / Seaborn)
3οΈβ£ Key Interview Areas
A. Python & Coding
β’ Write code to clean and analyze data
β’ Solve logic problems (e.g., reverse a list, group data by key)
β’ List vs Dict vs DataFrame usage
B. Statistics & Probability
β’ Hypothesis testing
β’ p-values, confidence intervals
β’ Normal distribution, sampling
C. Machine Learning Concepts
β’ Supervised vs unsupervised learning
β’ Overfitting, regularization, cross-validation
β’ Algorithms: Linear Regression, Decision Trees, KNN, SVM
D. SQL
β’ Joins, GROUP BY, subqueries
β’ Window functions
β’ Data aggregation and filtering
E. Business & Communication
β’ Explain model results to non-tech stakeholders
β’ What metrics would you track for [business case]?
β’ Tell me about a time you used data to influence a decision
4οΈβ£ Build Your Portfolio
β Do projects like:
β’ E-commerce sales analysis
β’ Customer churn prediction
β’ Movie recommendation system
β Host on GitHub or Kaggle
β Add visual dashboards and insights
5οΈβ£ Practice Platforms
β’ LeetCode (SQL, Python)
β’ HackerRank
β’ StrataScratch (SQL case studies)
β’ Kaggle (competitions & notebooks)
π¬ Tap β€οΈ for more!
β€16π2
Which library is used for basic plotting in Python?
Anonymous Quiz
5%
A) NumPy
8%
B) Pandas
83%
C) Matplotlib
4%
D) TensorFlow
β€3π1
Which function is used to display a plot?
Anonymous Quiz
6%
A) showplot()
5%
B) display()
70%
C) plt.show()
19%
D) plot.show()
β€4
What type of chart is best for showing trends over time?
Anonymous Quiz
13%
A) Bar chart
6%
B) Pie chart
67%
C) Line chart
14%
D) Histogram
β€4
Which library is used for advanced and attractive visualizations?
Anonymous Quiz
20%
A) Matplotlib
69%
B) Seaborn
6%
C) NumPy
4%
D) SciPy
β€4
What does a histogram show?
Anonymous Quiz
31%
A) Relationship between two variables
10%
B) Categories
58%
C) Distribution of data
1%
D) Exact values
β€4π1
β
Exploratory Data Analysis (EDA) ππ
EDA is where you understand your data before building any model.
πΉ 1. What is EDA?
EDA = Exploring and analyzing data to find patterns, trends, and insights
Before ML, always do EDA.
π₯ 2. Why EDA is Important?
β Understand data structure
β Find missing values
β Detect outliers
β Discover patterns relationships
Without EDA = wrong conclusions β
πΉ 3. Basic EDA Steps
Step 1: Load Data
Step 2: View Data
Step 3: Check Data Info
Step 4: Check Missing Values
Step 5: Check Unique Values
Step 6: Correlation (Very Important β)
Helps understand relationships between variables.
π₯ 4. Visualization in EDA
Histogram
Boxplot (Outlier Detection β)
Heatmap (Correlation)
πΉ 5. What You Should Find in EDA?
β Trends
β Patterns
β Outliers
β Relationships
π― Todayβs Goal
β Perform basic EDA
β Understand dataset structure
β Identify issues in data
β Visualize key insights
π¬ Tap β€οΈ for more!
EDA is where you understand your data before building any model.
πΉ 1. What is EDA?
EDA = Exploring and analyzing data to find patterns, trends, and insights
Before ML, always do EDA.
π₯ 2. Why EDA is Important?
β Understand data structure
β Find missing values
β Detect outliers
β Discover patterns relationships
Without EDA = wrong conclusions β
πΉ 3. Basic EDA Steps
Step 1: Load Data
import pandas as pd
df = pd.read_csv("data.csv")
Step 2: View Data
df.head()
df.tail()
Step 3: Check Data Info
df.info()
df.describe()
Step 4: Check Missing Values
df.isnull().sum()
Step 5: Check Unique Values
df["column_name"].value_counts()
Step 6: Correlation (Very Important β)
df.corr()
Helps understand relationships between variables.
π₯ 4. Visualization in EDA
Histogram
df["Age"].hist()
Boxplot (Outlier Detection β)
import seaborn as sns
sns.boxplot(x=df["Age"])
Heatmap (Correlation)
sns.heatmap(df.corr(), annot=True)
πΉ 5. What You Should Find in EDA?
β Trends
β Patterns
β Outliers
β Relationships
π― Todayβs Goal
β Perform basic EDA
β Understand dataset structure
β Identify issues in data
β Visualize key insights
π¬ Tap β€οΈ for more!
β€20π3
What is the main purpose of EDA?
Anonymous Quiz
9%
A) Build machine learning models
3%
B) Deploy applications
86%
C) Understand and analyze data
3%
D) Write code
β€2
Which function is used to view the first 5 rows of a dataset?
Anonymous Quiz
3%
A) df.start()
82%
B) df.head()
9%
C) df.top()
5%
D) df.first()
β€5
Which function provides summary statistics of data?
Anonymous Quiz
18%
A) df.info()
48%
B) df.describe()
23%
C) df.summary()
11%
D) df.stats()
β€1