Conditions in Python: My Decision-Making Guide

Author: Mohammad Sayem Chowdhury

Welcome! In this notebook, I'll share my journey understanding conditional statements in Python. Conditions are the backbone of decision-making in programming, and mastering them has been crucial for creating intelligent, responsive code. By the end, you'll see how I approach comparison operators, branching, and logical operations.

What I'll Cover

• Comparison Operators
• If, Elif, and Else Statements
• Logical Operators (and, or, not)
• Nested Conditions
• Practical Decision-Making Examples

Estimated time: about 20 minutes of logical exploration.

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Comparison Operators: My Foundation

Comparison operators are how I make my programs smart. They compare values and return True or False, which becomes the basis for all decision-making:

• Equal: == (checks if values are the same)
• Not equal: != (checks if values are different)
• Greater than: >
• Less than: <
• Greater than or equal: >=
• Less than or equal: <=

# My personal data for examples
my_age = 25
my_height = 175  # in cm
my_name = "Mohammad Sayem Chowdhury"
my_gpa = 3.8

print("My information:")
print(f"Age: {my_age}")
print(f"Height: {my_height} cm")
print(f"Name: {my_name}")
print(f"GPA: {my_gpa}")
print()

# Testing equality
print("Equality comparisons:")
print(f"Is my age exactly 25? {my_age == 25}")
print(f"Is my name 'Mohammad'? {my_name == 'Mohammad'}")
print(f"Is my GPA exactly 4.0? {my_gpa == 4.0}")
print()

# Testing inequality
print("Inequality comparisons:")
print(f"Is my age not 30? {my_age != 30}")
print(f"Is my height not 180cm? {my_height != 180}")

# Numerical comparisons with my data
print("Numerical comparisons:")
print(f"Am I older than 20? {my_age > 20}")
print(f"Am I younger than 30? {my_age < 30}")
print(f"Is my height at least 170cm? {my_height >= 170}")
print(f"Is my GPA at most 4.0? {my_gpa <= 4.0}")
print()

# Comparing different data types
favorite_number = 7
lucky_number = "7"
print("Type comparison:")
print(f"Favorite number: {favorite_number} (type: {type(favorite_number)})")
print(f"Lucky number: {lucky_number} (type: {type(lucky_number)})")
print(f"Are they equal? {favorite_number == lucky_number}")
print(f"Are they equal after conversion? {favorite_number == int(lucky_number)}")

Branching: Making Decisions

This is where conditions become powerful! I use if, elif, and else to make my programs respond differently based on conditions:

# Simple if statement
current_hour = 14  # 2 PM in 24-hour format

if current_hour < 12:
    greeting = "Good morning!"
    print(greeting)

print(f"Current time: {current_hour}:00")

# If-else statement
temperature = 22  # Celsius

if temperature >= 25:
    print("It's a warm day! Perfect for outdoor activities.")
    outfit = "Light clothes"
else:
    print("It's a cool day. Maybe stay indoors or dress warmly.")
    outfit = "Warm clothes"

print(f"Temperature: {temperature}°C")
print(f"Recommended outfit: {outfit}")

# Multiple conditions with elif
def get_grade_feedback(score):
    """My grading system with personalized feedback."""
    if score >= 90:
        grade = 'A'
        feedback = "Excellent work! You're mastering the material."
    elif score >= 80:
        grade = 'B'
        feedback = "Good job! You have a solid understanding."
    elif score >= 70:
        grade = 'C'
        feedback = "Fair work. Consider reviewing key concepts."
    elif score >= 60:
        grade = 'D'
        feedback = "You're passing, but there's room for improvement."
    else:
        grade = 'F'
        feedback = "Let's work together to improve your understanding."
    
    return grade, feedback

# Testing my grading system
test_scores = [95, 87, 73, 65, 45]

for score in test_scores:
    grade, feedback = get_grade_feedback(score)
    print(f"Score: {score} | Grade: {grade} | {feedback}")

Logical Operators: Combining Conditions

I often need to combine multiple conditions. Python's logical operators help me create complex decision trees:

• and: Both conditions must be True
• or: At least one condition must be True
• not: Reverses the boolean value

# Personal eligibility checker
age = 25
has_degree = True
years_experience = 3
speaks_english = True

print("Checking job eligibility...")
print(f"Age: {age}")
print(f"Has degree: {has_degree}")
print(f"Years of experience: {years_experience}")
print(f"Speaks English: {speaks_english}")
print()

# Using 'and' operator
if age >= 18 and has_degree:
    print("✓ Meets basic requirements (age and education)")
else:
    print("✗ Does not meet basic requirements")

# Using 'or' operator  
if years_experience >= 5 or has_degree:
    print("✓ Meets experience/education requirement")
else:
    print("✗ Needs more experience or education")

# Using 'not' operator
if not (age < 18):
    print("✓ Is an adult")
else:
    print("✗ Is a minor")

# Complex condition combining all operators
if (age >= 21 and has_degree) and (years_experience >= 2 or speaks_english):
    print("✓ HIRED! Welcome to the team!")
else:
    print("✗ Not quite there yet, but keep improving!")

# Weather decision system
temperature = 20
is_raining = False
is_weekend = True
have_umbrella = True

print("Weather Decision System")
print(f"Temperature: {temperature}°C")
print(f"Raining: {is_raining}")
print(f"Weekend: {is_weekend}")
print(f"Have umbrella: {have_umbrella}")
print()

# Decision making with multiple logical operators
if temperature > 25 and not is_raining:
    activity = "Go to the beach or have a picnic"
elif temperature > 15 and (not is_raining or have_umbrella):
    activity = "Take a walk in the park"
elif is_weekend and temperature > 10:
    activity = "Visit a museum or go shopping"
else:
    activity = "Stay home with a good book and hot tea"

print(f"Recommended activity: {activity}")

# Complex logical expression
perfect_day = (temperature >= 20 and temperature <= 28) and not is_raining and is_weekend
print(f"Is it a perfect day? {perfect_day}")

Nested Conditions: Advanced Decision Trees

Sometimes I need multiple levels of conditions for complex scenarios:

# Academic scholarship eligibility system
def check_scholarship_eligibility(gpa, family_income, extracurriculars, essay_score):
    """My scholarship evaluation system."""
    print(f"Evaluating scholarship application:")
    print(f"GPA: {gpa}")
    print(f"Family Income: ${family_income:,}")
    print(f"Extracurricular Activities: {extracurriculars}")
    print(f"Essay Score: {essay_score}/100")
    print()
    
    if gpa >= 3.5:
        print("✓ Academic requirement met (GPA ≥ 3.5)")
        
        if family_income <= 50000:
            print("✓ Financial need requirement met")
            
            if extracurriculars >= 2:
                print("✓ Extracurricular requirement met")
                
                if essay_score >= 80:
                    scholarship = "Full Scholarship ($10,000)"
                elif essay_score >= 70:
                    scholarship = "Partial Scholarship ($5,000)"
                else:
                    scholarship = "Merit Award ($1,000)"
            else:
                print("✗ Insufficient extracurricular activities")
                scholarship = "Merit Award ($1,000)" if essay_score >= 75 else "Not eligible"
        
        elif family_income <= 100000:
            print("• Moderate financial need")
            if extracurriculars >= 3 and essay_score >= 85:
                scholarship = "Partial Scholarship ($3,000)"
            else:
                scholarship = "Merit Award ($1,000)"
        
        else:
            print("• No financial need")
            if extracurriculars >= 4 and essay_score >= 90:
                scholarship = "Excellence Award ($2,000)"
            else:
                scholarship = "Recognition Certificate"
    
    else:
        print("✗ Academic requirement not met (GPA < 3.5)")
        scholarship = "Not eligible"
    
    return scholarship

# Test different scenarios
applicants = [
    ("Mohammad", 3.8, 35000, 3, 85),
    ("Sarah", 3.9, 75000, 4, 92),
    ("Ahmed", 3.2, 40000, 2, 80),
    ("Lisa", 3.6, 120000, 5, 95)
]

for name, gpa, income, activities, essay in applicants:
    print(f"=== {name}'s Application ===")
    result = check_scholarship_eligibility(gpa, income, activities, essay)
    print(f"Result: {result}")
    print("-" * 40)

Practical Applications: Real-World Examples

Let me show how I use conditions in everyday programming scenarios:

# Password strength validator
def validate_password(password):
    """My password strength checking system."""
    score = 0
    feedback = []
    
    # Length check
    if len(password) >= 8:
        score += 1
        feedback.append("✓ Length is adequate (8+ characters)")
    else:
        feedback.append("✗ Password too short (needs 8+ characters)")
    
    # Uppercase check
    if any(c.isupper() for c in password):
        score += 1
        feedback.append("✓ Contains uppercase letters")
    else:
        feedback.append("✗ Needs uppercase letters")
    
    # Lowercase check
    if any(c.islower() for c in password):
        score += 1
        feedback.append("✓ Contains lowercase letters")
    else:
        feedback.append("✗ Needs lowercase letters")
    
    # Number check
    if any(c.isdigit() for c in password):
        score += 1
        feedback.append("✓ Contains numbers")
    else:
        feedback.append("✗ Needs numbers")
    
    # Special character check
    special_chars = "!@#$%^&*()_+-=[]{}|;:,.<>?"
    if any(c in special_chars for c in password):
        score += 1
        feedback.append("✓ Contains special characters")
    else:
        feedback.append("✗ Needs special characters")
    
    # Determine strength
    if score >= 5:
        strength = "Very Strong"
    elif score >= 4:
        strength = "Strong"
    elif score >= 3:
        strength = "Moderate"
    elif score >= 2:
        strength = "Weak"
    else:
        strength = "Very Weak"
    
    return strength, score, feedback

# Test different passwords
test_passwords = [
    "password123",
    "MySecureP@ss123",
    "weakpw",
    "StrongPassword2024!",
    "12345678"
]

for pwd in test_passwords:
    strength, score, feedback = validate_password(pwd)
    print(f"Password: {'*' * len(pwd)} (length: {len(pwd)})")
    print(f"Strength: {strength} ({score}/5)")
    for comment in feedback:
        print(f"  {comment}")
    print("-" * 50)

# Personal budget tracker with conditions
def analyze_spending(income, expenses):
    """My personal finance analysis system."""
    total_expenses = sum(expenses.values())
    savings = income - total_expenses
    savings_rate = (savings / income) * 100 if income > 0 else 0
    
    print(f"Monthly Income: ${income:,.2f}")
    print(f"Total Expenses: ${total_expenses:,.2f}")
    print(f"Savings: ${savings:,.2f}")
    print(f"Savings Rate: {savings_rate:.1f}%")
    print()
    
    # Financial health assessment
    if savings_rate >= 20:
        status = "Excellent"
        advice = "Great job! You're building a strong financial foundation."
    elif savings_rate >= 10:
        status = "Good"
        advice = "You're doing well! Consider increasing savings gradually."
    elif savings_rate >= 5:
        status = "Fair"
        advice = "You're saving something, but try to reduce unnecessary expenses."
    elif savings_rate > 0:
        status = "Poor"
        advice = "Your savings are minimal. Review your budget carefully."
    else:
        status = "Critical"
        advice = "You're spending more than you earn. Immediate action needed!"
    
    print(f"Financial Status: {status}")
    print(f"Advice: {advice}")
    print()
    
    # Expense category analysis
    print("Expense Analysis:")
    for category, amount in expenses.items():
        percentage = (amount / income) * 100
        if percentage > 30:
            flag = "⚠️ HIGH"
        elif percentage > 20:
            flag = "⚡ MODERATE"
        else:
            flag = "✅ NORMAL"
        
        print(f"{category}: ${amount:,.2f} ({percentage:.1f}%) {flag}")

# My monthly budget
my_income = 5000
my_expenses = {
    "Rent": 1200,
    "Food": 600,
    "Transportation": 300,
    "Utilities": 200,
    "Entertainment": 400,
    "Savings_Investment": 1000,
    "Miscellaneous": 200
}

analyze_spending(my_income, my_expenses)

# Smart home automation system
def smart_home_controller(time_hour, temperature, occupancy, day_of_week):
    """My smart home decision system."""
    actions = []
    
    # Lighting control
    if occupancy and (time_hour < 7 or time_hour > 18):
        actions.append("Turn on lights")
    elif not occupancy or (7 <= time_hour <= 18):
        actions.append("Turn off lights")
    
    # Heating/cooling control
    if occupancy:
        if temperature < 20:
            actions.append("Turn on heating to 22°C")
        elif temperature > 26:
            actions.append("Turn on AC to 24°C")
        else:
            actions.append("Maintain current temperature")
    else:
        if temperature < 16:
            actions.append("Set heating to 18°C (energy saving)")
        elif temperature > 28:
            actions.append("Set AC to 26°C (energy saving)")
        else:
            actions.append("Turn off climate control")
    
    # Security system
    if not occupancy and (time_hour < 6 or time_hour > 22):
        actions.append("Activate full security mode")
    elif not occupancy:
        actions.append("Activate basic security mode")
    else:
        actions.append("Deactivate security system")
    
    # Weekend special rules
    if day_of_week in [6, 7]:  # Weekend
        if occupancy and 8 <= time_hour <= 10:
            actions.append("Play relaxing music")
        if time_hour == 19:  # 7 PM
            actions.append("Dim lights for movie time")
    
    return actions

# Simulate different scenarios
scenarios = [
    ("Monday 8AM", 8, 18, True, 1),
    ("Tuesday 2PM", 14, 24, False, 2),
    ("Friday 7PM", 19, 22, True, 5),
    ("Saturday 9AM", 9, 19, True, 6),
    ("Sunday 11PM", 23, 25, False, 7)
]

for desc, hour, temp, occupied, day in scenarios:
    print(f"=== {desc} ===")
    print(f"Temperature: {temp}°C, Occupied: {occupied}")
    actions = smart_home_controller(hour, temp, occupied, day)
    for action in actions:
        print(f"• {action}")
    print()

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My Key Takeaways

Mastering conditions has transformed how I write Python code. Here's what I consider most important:

1. Comparison Operators: The foundation of all decision-making in code
2. Logical Operators: Enable complex, multi-factor decisions
3. Nested Conditions: Allow sophisticated decision trees for complex scenarios
4. Clean Structure: Well-organized if-elif-else chains make code readable
5. Real-World Applications: Conditions are everywhere - from validation to automation

I use conditions for:

• Input validation and error checking
• User authentication and authorization
• Data filtering and categorization
• Business logic implementation
• Automated decision systems
• Game development and interactive applications

The key is to think logically about decision-making and translate that into clear, readable conditional statements.

Copyright © 2025 Mohammad Sayem Chowdhury. This notebook and its content are shared for personal learning and inspiration.

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Next Steps in My Conditional Logic Journey

Understanding conditions opened the door to loops, functions, and object-oriented programming. Every advanced Python concept builds on this foundation of logical decision-making.

— Mohammad Sayem Chowdhury