PHP Loops
A loop runs the same code again and again, so you do not have to write it many times.
Types of Loops
| Loop | Use it when |
|---|---|
while | You repeat while a condition is true |
do...while | Like while, but the code runs at least once |
for | You know how many times to repeat |
foreach | You go through every item in an array |
The while Loop
Example
php
<?php
$i = 1;
while ($i <= 5) {
echo "Lesson $i<br>";
$i++;
}Output
Lesson 1 Lesson 2 Lesson 3 Lesson 4 Lesson 5
Always change the variable inside the loop (here $i++). If the condition never becomes false, you get an infinite loop and the page never finishes loading.
The do...while Loop
The condition is checked after the code, so the code runs at least once:
Example
php
<?php
$tries = 10;
do {
echo "Attempt number $tries<br>";
$tries++;
} while ($tries < 5);Output
Attempt number 10
The for Loop
A for loop puts the start, the condition and the step on one line:
Example
php
<?php
// Multiplication table of 7
for ($n = 1; $n <= 5; $n++) {
echo "7 x $n = " . (7 * $n) . "<br>";
}Output
7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35
The foreach Loop
foreach is the easiest way to go through an array:
Example
php
<?php
$courses = ["Web Development", "Graphic Designing", "SEO"];
foreach ($courses as $course) {
echo "- $course<br>";
}Output
- Web Development - Graphic Designing - SEO
With keys and values:
Example
php
<?php
$prices = ["Tea" => 80, "Paratha" => 60, "Samosa" => 30];
foreach ($prices as $item => $price) {
echo "$item: Rs $price<br>";
}Output
Tea: Rs 80 Paratha: Rs 60 Samosa: Rs 30
break and continue
breakstops the loop completelycontinueskips the rest of this round and goes to the next one
Example
php
<?php
for ($i = 1; $i <= 10; $i++) {
if ($i % 2 === 0) {
continue; // skip even numbers
}
if ($i > 7) {
break; // stop after 7
}
echo "$i ";
}Output
1 3 5 7
Adding Up with a Loop
Example
php
<?php
$marks = [78, 85, 62, 90];
$total = 0;
foreach ($marks as $m) {
$total += $m;
}
echo "Total: $total, Average: " . ($total / count($marks));Output
Total: 315, Average: 78.75
Exercise
Exercise
Which loop is best for going through every item of an array?