PHP · Theory

Indexed Array

Theory

34/352

Indexed Array

An array holds many values. Indexed: $marks = [72, 40, 88]; $marks[0] is 72. Associative: $student = ['name' => 'Asha', 'roll' => 12]; $student['name'] is Asha. foreach ($student as $key => $value) walks them.

count($arr) length. array_push / $arr[] = 10 to add. PHP arrays are ordered maps — that’s why both styles work.

Trap — mixing 0 and '0' carelessly. Trap: foreach ($arr as &$v) then using $v later (reference leak).

Exam tip

Indexed [72,40] and associative ['name'=>'Asha'].

Example

<?php
$langs = ["PHP", "JS", "SQL"];
$langs[] = "Python";
foreach ($langs as $i => $lang) {
  echo "$i: $lang\n";
}

Indexed Array — pHP arrays are ordered maps. foreach walks key and value.

Short notes

DefArray = list or name→value map.
Rule[1,2] or ['name'=>'Asha']. foreach to loop.
Trapforeach by reference leftover.

PHP · Theory

Indexed Array

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Theory

34/352

Indexed Array

count($arr) length. array_push / $arr[] = 10 to add. PHP arrays are ordered maps — that’s why both styles work.

Trap — mixing 0 and '0' carelessly. Trap: foreach ($arr as &$v) then using $v later (reference leak).

Exam tip

Indexed [72,40] and associative ['name'=>'Asha'].

Example

<?php
$langs = ["PHP", "JS", "SQL"];
$langs[] = "Python";
foreach ($langs as $i => $lang) {
  echo "$i: $lang\n";
}

Indexed Array — pHP arrays are ordered maps. foreach walks key and value.

Short notes

DefArray = list or name→value map.
Rule[1,2] or ['name'=>'Asha']. foreach to loop.
Trapforeach by reference leftover.

Indexed Array

Example

Short notes

Questions

Indexed Array

Example

Short notes

Questions