PHP · Theory

Variable Scope

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Theory

10/352

Variable Scope

If you can teach Variable Scope using $marks = 72, you know it. If you only know the heading, you don’t.

Do Variable Scope once by hand. $name = 'Asha';. Change one input. Say the new result out loud.

Without Variable Scope, a result script gets messy and $marks = 72 is hard to trust.

Variable Scope shows up in a result script. Name $marks = 72, not “a real-world scenario”.

Variable Scope trap — using marks without $. Ananya loses marks for that every viva.

After Variable Scope, Ananya should still remember using marks without $.

Close Variable Scope with — “If I skip it, $marks = 72 goes wrong like this: using marks without $.”

Exam tip

Say Variable Scope in one breath, then $name = 'Asha';, then using marks without $.

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

DefVariable Scope — Ananya uses it for $marks = 72 in a result script.
RuleVariable Scope → $name = 'Asha';.
RememberVariable Scope + the PHP runtime (a result script).
UseVariable Scope in a result script ($marks = 72).
TrapVariable Scope — using marks without $.
ExVariable Scope → $marks = 72.

PHP · Theory

Variable Scope

← All stacks

Theory

10/352

Variable Scope

If you can teach Variable Scope using $marks = 72, you know it. If you only know the heading, you don’t.

Do Variable Scope once by hand. $name = 'Asha';. Change one input. Say the new result out loud.

Without Variable Scope, a result script gets messy and $marks = 72 is hard to trust.

Variable Scope shows up in a result script. Name $marks = 72, not “a real-world scenario”.

Variable Scope trap — using marks without $. Ananya loses marks for that every viva.

After Variable Scope, Ananya should still remember using marks without $.

Close Variable Scope with — “If I skip it, $marks = 72 goes wrong like this: using marks without $.”

Exam tip

Say Variable Scope in one breath, then $name = 'Asha';, then using marks without $.

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

DefVariable Scope — Ananya uses it for $marks = 72 in a result script.
RuleVariable Scope → $name = 'Asha';.
RememberVariable Scope + the PHP runtime (a result script).
UseVariable Scope in a result script ($marks = 72).
TrapVariable Scope — using marks without $.
ExVariable Scope → $marks = 72.

Variable Scope

Example

Short notes

Questions

Variable Scope

Example

Short notes

Questions