🔁 PHP Control Flow & Logic – Guide to Conditional and Looping Constructs

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🧲 Introduction – Why Learn PHP Control Flow?

Every program makes decisions and executes repetitive tasks. PHP’s control flow structures like if, switch, and loops (for, while, foreach) allow developers to write logical, dynamic, and responsive code.

Mastering control flow empowers you to:

• 🧠 Make data-driven decisions
• 🔁 Execute tasks repeatedly
• ⛔ Skip or terminate loops gracefully

🎯 In this guide, you’ll learn how to:

• Use conditional and loop statements
• Control logic using if, switch, break, and continue
• Iterate over arrays and objects using loops and iterables

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📘 Topics Covered

🔖 Topic	📄 Description
🛤️ PHP Control Statements	Overview of control logic constructs
🧠 PHP Decision Making	Execute code conditionally
❗ PHP if…else Statement	Basic conditional branching
🔀 PHP Switch Statement	Handle multiple values elegantly
🔁 PHP Loop Types	Overview of looping constructs
🔂 PHP For Loop	Loop using a counter
🔄 PHP Foreach Loop	Loop through arrays/objects
🔁 PHP While Loop	Loop based on a condition
🔃 PHP Do…While Loop	Ensure code runs at least once
⛔ PHP Break Statement	Exit loops or switch blocks
⏭️ PHP Continue Statement	Skip to the next iteration
🔄 PHP Iterables	Loop through iterable objects and arrays

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🛤️ PHP Control Statements – Structure Flow of Execution

Control statements allow conditional execution, repetition, or redirection of code logic. Includes:

• if, else, elseif
• switch
• for, foreach, while, do…while
• break, continue

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🧠 PHP Decision Making – Evaluate Conditions

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

✅ Decision-making is central to dynamic PHP applications.

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❗ PHP if…else Statement – Core Conditional Logic

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

✅ Use if…else and elseif to handle multiple branches.

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🔀 PHP Switch Statement – Handle Multiple Cases

$day = "Monday";
switch ($day) {
  case "Monday":
    echo "Start of week";
    break;
  case "Friday":
    echo "Weekend soon!";
    break;
  default:
    echo "Midweek day";
}

✅ Cleaner than multiple if…else statements for fixed values.

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🔁 PHP Loop Types – Repeat Code Efficiently

PHP provides four loop types:

• for
• foreach
• while
• do…while

Used to execute code blocks repeatedly based on conditions or data structures.

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🔂 PHP For Loop – Counter-Based Iteration

for ($i = 1; $i <= 5; $i++) {
  echo $i;
}

✅ Best when you know how many times to loop.

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🔄 PHP Foreach Loop – Iterate Arrays & Objects

$colors = ["red", "blue", "green"];
foreach ($colors as $color) {
  echo $color;
}

✅ Ideal for arrays and iterable objects.

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🔁 PHP While Loop – Conditional Iteration

$count = 1;
while ($count <= 3) {
  echo $count++;
}

✅ Repeats code as long as the condition is true.

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🔃 PHP Do…While Loop – Run First, Check Later

$i = 1;
do {
  echo $i;
  $i++;
} while ($i <= 3);

✅ Ensures the loop runs at least once.

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⛔ PHP Break Statement – Exit Loops Early

for ($i = 0; $i < 10; $i++) {
  if ($i == 5) break;
  echo $i;
}

✅ Stops loop execution immediately.

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⏭️ PHP Continue Statement – Skip Iterations

for ($i = 0; $i < 5; $i++) {
  if ($i == 2) continue;
  echo $i;
}

✅ Skips current loop iteration and continues to the next.

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🔄 PHP Iterables – Loop Over Iterable Objects

PHP supports iterable as a type hint (PHP 7.1+):

function printItems(iterable $items) {
  foreach ($items as $item) {
    echo $item;
  }
}

✅ Accepts arrays and objects that implement Traversable.

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📘 Best Practices for PHP Control Flow

✅ Do This	🚫 Avoid This
Use foreach for arrays	Don’t use for unless needed
Combine break with switch	Don’t forget break – it causes fall-through
Use continue to skip logic	Avoid deeply nested if conditions
Prefer switch over many if…else	Don’t duplicate logic across branches

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📌 Summary – Recap & Next Steps

Control flow is essential for decision-making and repetition in PHP. From conditional branching to efficient looping, these constructs empower your code with logic and adaptability.

🔍 Key Takeaways:

• Use if…else and switch for branching
• Apply for, foreach, while, and do…while for loops
• Control flow inside loops with break, continue, and iterable types

⚙️ Real-World Relevance:
Used in form processing, user validation, dashboard rendering, data processing, and backend automation.

➡️ Next Topic: Explore 🔧 PHP Functions & Scope – Define and Reuse Logic Blocks.

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❓ FAQs – PHP Control Flow & Logic

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❓ What is the difference between while and do…while?
✅ while checks the condition first, while do…while executes the block at least once before checking the condition.

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❓ When should I use switch over if…else?
✅ Use switch when you’re comparing the same variable to multiple fixed values.

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❓ How do I stop a loop early in PHP?
✅ Use the break statement inside your loop when a condition is met.

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❓ Can I use loops with objects in PHP?
✅ Yes. Use foreach with objects that implement the Iterator or Traversable interface.

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❓ What does iterable mean in PHP?
✅ It’s a type that allows functions to accept either arrays or iterable objects like Generator.

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