❗ PHP — If…Else Statement

A focused guide on how to use if, else, and elseif for decision-making in PHP applications.

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🧲 Introduction – Why if...else Is Essential in PHP

The if...else statement is the most fundamental tool for making decisions in PHP. Whether you’re checking user permissions, validating input, or managing state, if...else structures let your code react dynamically to conditions.

🎯 In this guide, you’ll learn:

• The basic syntax of if, else, and elseif
• How to nest and chain conditions
• When to use elseif vs else
• Practical examples for real-world use

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✅ Basic if Statement

$age = 21;

if ($age >= 18) {
    echo "You are eligible to vote.";
}

🔍 Output: You are eligible to vote.

📘 Executes the block only when the condition is true.

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🔁 if...else Structure

$loggedIn = false;

if ($loggedIn) {
    echo "Welcome back!";
} else {
    echo "Please log in.";
}

🔍 Output: Please log in.

📘 Adds an alternate block when the condition is false.

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🔂 if...elseif...else Chain

$marks = 70;

if ($marks >= 90) {
    echo "Grade A";
} elseif ($marks >= 75) {
    echo "Grade B";
} elseif ($marks >= 60) {
    echo "Grade C";
} else {
    echo "Grade D";
}

🔍 Output: Grade C

📘 Useful when multiple conditions must be evaluated in sequence.

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🧠 Nested if...else

$user = "admin";
$loggedIn = true;

if ($loggedIn) {
    if ($user === "admin") {
        echo "Admin Panel";
    } else {
        echo "User Dashboard";
    }
} else {
    echo "Login Required";
}

🔍 Output: Admin Panel

📘 if blocks can be nested, but avoid deep nesting for clarity.

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📏 Comparison Operators Recap

Operator	Description	Example	Result
==	Equal (value)	5 == "5"	true
===	Identical (value+type)	5 === "5"	false
!=	Not equal	5 != 3	true
>	Greater than	5 > 3	true
<	Less than	5 < 3	false

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🧠 Best Practices

• ✅ Always use {} braces for clarity — even in one-liners
• ✅ Prefer === over == to avoid type coercion bugs
• ✅ Break down long conditions using logical operators (&&, ||)
• ❌ Avoid deeply nested if statements — use early returns when possible

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📌 Summary – Recap & Next Steps

The if...else structure enables your PHP programs to react to conditions and guide execution paths. It’s the most used logic structure in real-world PHP development.

🔍 Key Takeaways:

• Use if for single condition
• Add else for alternate paths
• Chain with elseif for multiple branches
• Use === for strict comparison

⚙️ Real-World Relevance:
Used in login authentication, form validation, feature toggling, access control, and more.

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❓ Frequently Asked Questions (FAQs)

❓ Can I omit else if I don’t need an alternative?
✅ Yes, else is optional.

❓ What’s the difference between == and ===?
✅ == compares values, === compares values and types.

❓ How many elseif conditions can I have?
✅ As many as needed. PHP checks them top-down.

❓ Can if statements be nested?
✅ Yes, but avoid more than 2–3 levels for readability.

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