PHP Loop: For, ForEach, While, Do While [Example]

By : Fiona Brown Fiona Brown
Hours Updated

⚡ Smart Summary

PHP Loops repeat a block of code until a condition is met, which removes repetitive typing and drives array processing. This walkthrough covers the four PHP loop types, for, foreach, while, and do-while, with syntax, flowcharts, and working output for each.

  • 🔁 What Loops Do: A loop runs the same block repeatedly until its condition is satisfied, saving you from writing duplicate statements.
  • 🔢 For Loop: for combines the counter, condition, and increment on one line, making it ideal when the iteration count is known.
  • 📦 Foreach Loop: foreach iterates through every element of an indexed or associative array without a manual counter.
  • 🔄 While Loop: while checks its condition before each pass, so the body may run zero times if the condition starts false.
  • 1️⃣ Do-While Loop: do-while checks the condition after the body, which guarantees the code block executes at least once.
  • 🧭 Choosing a Loop: Pick for and foreach for counting and arrays, while for condition-driven repeats, and do-while when one guaranteed pass is required.
  • 🤖 AI Assist: AI tools can refactor loops, convert a for loop into array functions, and locate the cause of an infinite loop.
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PHP Loops

A loop is an iterative control structure that involves executing the same block of code a number of times until a certain condition is met. PHP supports four loop types, compared in the table below.

Loop Best for Condition checked Runs at least once
for A known number of iterations Before each iteration No
foreach Iterating over array elements Per array element No
while Repeating while a condition holds Before each iteration No
do-while Running once, then re-checking After each iteration Yes

PHP For Loop

The for loop executes a block of code a specified number of times. It is the right choice when you know in advance how many iterations are needed.

Syntax. It has the following basic syntax.

<?php
for (initialize; condition; increment){

// code to be executed

}
?>

HERE,

  • “for…{…}” is the loop block
  • “initialize” is usually an integer; it is used to set the counter’s initial value.
  • “condition” is the condition that is evaluated for each PHP execution. If it evaluates to true, then execution of the for loop continues. If it evaluates to false, the execution of the for loop is terminated.
  • “increment” is used to increment the initial value of the counter integer.

How it works. The flowchart shown below illustrates how the for loop in PHP works.

PHP For Loop

How to code. The code below uses the for loop to print the values of multiplying 10 by 0 through to 9.

<?php

for ($i = 0; $i < 10; $i++){

$product = 10 * $i;

echo "The product of 10 * $i is $product <br/>";
}

?>

Output:

The product of 10 * 0 is 0
The product of 10 * 1 is 10
The product of 10 * 2 is 20
The product of 10 * 3 is 30
The product of 10 * 4 is 40
The product of 10 * 5 is 50
The product of 10 * 6 is 60
The product of 10 * 7 is 70
The product of 10 * 8 is 80
The product of 10 * 9 is 90

PHP Foreach Loop

The PHP foreach loop is used to iterate through array values. It has the following basic syntax.

<?php
foreach($array_variable as $array_values){

block of code to be executed

}
?>

HERE,

  • “foreach(…){…}” is the foreach loop block code
  • “$array_variable” is the array variable to be looped through
  • “$array_values” is the temporary variable that holds the current array item value.
  • “block of code…” is the piece of code that operates on the array values

How it works. The flowchart shown below illustrates how the foreach loop works.

PHP For Each loop

Practical examples. The code below uses the foreach loop to read and print the elements of an array.

<?php

$animals_list = array("Lion","Wolf","Dog","Leopard","Tiger");

foreach($animals_list as $array_values){

echo $array_values . "<br>";

}

?>

Output:

Lion
Wolf
Dog
Leopard
Tiger

Let us look at another example that loops through an associative array. An associative array uses alphanumeric words for access keys.

<?php

$persons = array("Mary" => "Female", "John" => "Male", "Mirriam" => "Female");

foreach($persons as $key => $value){

echo "$key is $value"."<br>";

}

?>

The names have been used as array keys and gender as the values.

Output:

Mary is Female
John is Male
Mirriam is Female

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PHP While Loop

The while loop is used to execute a block of code repeatedly until the set condition is satisfied.

When to use while loops

  • While loops are used to execute a block of code until a certain condition becomes true.
  • You can use a while loop to read records returned from a database.

Types of while loops

  • Do… while – executes the block of code at least once before evaluating the condition
  • While… – checks the condition first. If it evaluates to true, the block of code is executed as long as the condition is true. If it evaluates to false, the execution of the while loop is terminated.

While loop. It has the following syntax.

<?php
while (condition){

block of code to be executed;

}
?>

HERE,

  • “while(…){…}” is the while loop block code
  • “condition” is the condition to be evaluated by the while loop
  • “block of code…” is the code to be executed if the condition gets satisfied

How it works. The flow chart shown below illustrates how the while loop works.

While Loop

Practical example. The code below uses the while loop to print numbers 1 to 5.

<?php

$i = 0;

while ($i < 5){

echo $i + 1 . "<br>";

$i++;

}

?>

Output:

1
2
3
4
5

PHP Do While Loop

The difference between the while loop and the do-while loop is that the do-while loop is executed at least once before the condition is evaluated.

Let us now look at the basic syntax of a do-while loop.

<?php
do{

block of code to be executed

} while(condition);
?>

HERE,

  • “do{…} while(…)” is the do-while loop block code
  • “condition” is the condition to be evaluated by the while loop
  • “block of code…” is the code that is executed at least once by the do-while loop

How it works. The flow chart shown below illustrates how the do-while loop works.

PHP Do While

Practical example. We are now going to modify the while loop example and implement it using the do-while loop, and set the counter initial value to 9.

The code below implements the above modified example.

<?php

$i = 9;

do{

echo "$i is"." <br>";

}
while($i < 9);

?>

The above code outputs:

9

Note: the above example outputs 9 only. This is because the do-while loop is executed at least once even if the set condition evaluates to false.

FAQs

Yes. Use array_reverse() with a foreach loop to walk the elements in reverse, or use a for loop that starts at count($array) – 1 and decrements the index down to zero.

The break statement accepts a number, so break 2; exits both the inner and the outer loop at once. This is cleaner than using a flag variable to stop the outer loop.

An infinite loop never ends because its condition never becomes false, often due to a missing increment. Ensure the loop variable changes each pass, or add a break when a limit is reached.

Yes. AI can spot repeated work inside a loop, suggest moving it outside, and replace manual loops with array functions like array_map or array_filter where they make the code clearer.

Yes. AI can rewrite an index-based for loop as a foreach when you are walking an array, or as array_map or array_sum when the loop just transforms or totals values. Test the output afterward.

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