PHP · Theory

Variable Scope

Theory

10/352

Variable Scope

A PHP variable starts with $ and a letter or underscore. $marks = 72; $name = 'Asha'; No type on the left by default. Types exist at runtime (int, string, array, object, null).

Names are case-sensitive — $Marks is not $marks. Assignment is = . Compare with == or === (=== also checks type).

Trap — marks = 72 without $. Trap: == vs = inside if ($marks = 40) which assigns.

Exam tip

$marks = 72; Names start with $.

Example

<?php
// Variable Scope
$scores = [80, 90, 70];
$avg = array_sum($scores) / count($scores);
echo "avg=" . number_format($avg, 1) . "\n";
foreach ($scores as $s) {
  if ($s >= 80) echo "high: $s\n";
}

Variable Scope: scores array, print avg, then high marks. Say the output.

Short notes

Def$name holds a value. Starts with $.
Rule= assign. === compare type+value.
TrapMissing $. = inside if.

PHP · Theory

Variable Scope

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Theory

10/352

Variable Scope

A PHP variable starts with $ and a letter or underscore. $marks = 72; $name = 'Asha'; No type on the left by default. Types exist at runtime (int, string, array, object, null).

Names are case-sensitive — $Marks is not $marks. Assignment is = . Compare with == or === (=== also checks type).

Trap — marks = 72 without $. Trap: == vs = inside if ($marks = 40) which assigns.

Exam tip

$marks = 72; Names start with $.

Example

<?php
// Variable Scope
$scores = [80, 90, 70];
$avg = array_sum($scores) / count($scores);
echo "avg=" . number_format($avg, 1) . "\n";
foreach ($scores as $s) {
  if ($s >= 80) echo "high: $s\n";
}

Variable Scope: scores array, print avg, then high marks. Say the output.

Short notes

Def$name holds a value. Starts with $.
Rule= assign. === compare type+value.
TrapMissing $. = inside if.

Variable Scope

Example

Short notes

Questions

Variable Scope

Example

Short notes

Questions