Loops in PHP (for, while, do-while, foreach)

What loops are for

A loop repeats a block of code many times, so you do not have to write it again and again. Want to print 1 to 100, or go through every item in a list? A loop does it in a few lines. PHP has four loops: for, while, do-while and foreach.

The for loop

Use for when you know how many times to repeat. It has three parts: start, condition, and update.

<?php
  for ($i = 1; $i <= 5; $i++) {
      echo $i . " ";
  }
?>

It reads as: start at $i = 1, keep going while $i <= 5, and add 1 each round ($i++). When $i becomes 6 the condition is false and the loop stops.

while and do-while

while checks the condition first; do-while runs once then checks.

<?php
  $i = 1;
  while ($i <= 3) {
      echo $i . " ";
      $i++;
  }
  // do-while always runs at least once:
  $n = 10;
  do {
      echo "run ";
  } while ($n < 5);
?>

Even though $n < 5 is false, the do-while printed "run" once because it checks the condition after running the body.

foreach (for arrays)

foreach is the easiest way to go through an array — no counter needed.

<?php
  $fruits = ["Apple", "Mango", "Banana"];
  foreach ($fruits as $fruit) {
      echo $fruit . " ";
  }
?>

For key-value arrays you can grab both: foreach ($ages as $name => $age) gives you the name and the age together each round.

break and continue

break leaves the loop early; continue skips just the current round.

<?php
  for ($i = 1; $i <= 5; $i++) {
      if ($i == 3) continue;  // skip 3
      if ($i == 5) break;     // stop before 5
      echo $i . " ";
  }
?>

3 is skipped by continue, and the loop stops at 5 because of break — so only 1, 2 and 4 print.

Common mistakes

• Forgetting to update the counter. Missing $i++ gives an infinite loop.
• Off-by-one errors. <= vs < changes how many times the loop runs — check the boundary.
• Using for when foreach is cleaner. For arrays, foreach avoids index mistakes.
• Changing the array while looping over it. This can cause skipped or repeated items.

Summary

• Loops repeat code so you write less and do more.
• for — when you know the count; while — repeat until a condition changes.
• do-while always runs at least once; foreach is best for arrays.
• break exits the loop; continue skips one round.
• Always ensure the loop can reach its end, or it runs forever.

Next, store the values you loop over with arrays in PHP, or make choices inside loops with if-else in PHP.