PHP · Theory

in_array()

Theory

125/352

in_array()

in_array() is a PHP array helper. You pass an array, you get a new array or a boolean/count. Example: in_array(40, $marks), array_merge($a,$b), count($marks).

foreach is still how you loop. Functions don’t replace understanding [ ] vs ['name'=>].

Trap — expecting the original array to change when the function returns a copy (array_map).

Exam tip

in_array(): one array, one function call, say the result.

Example

<?php
// in_array()
$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";
}

in_array(): scores array, print avg, then high marks. Say the output.

Short notes

Defin_array() — PHP array function.
RuleRead the return value. foreach to walk.
TrapThinking it always edits in place.

PHP · Theory

in_array()

← All stacks

Theory

125/352

in_array()

in_array() is a PHP array helper. You pass an array, you get a new array or a boolean/count. Example: in_array(40, $marks), array_merge($a,$b), count($marks).

foreach is still how you loop. Functions don’t replace understanding [ ] vs ['name'=>].

Trap — expecting the original array to change when the function returns a copy (array_map).

Exam tip

in_array(): one array, one function call, say the result.

Example

<?php
// in_array()
$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";
}

in_array(): scores array, print avg, then high marks. Say the output.

Short notes

Defin_array() — PHP array function.
RuleRead the return value. foreach to walk.
TrapThinking it always edits in place.

in_array()

Example

Short notes

Questions

in_array()

Example

Short notes

Questions