Arrays and Iteration

Array Count

Arrays group related values, and count reports how many elements are in the group.

array length The length of an array is the number of values it currently contains.

Array Count

extra
array_count.php
Replay: real traced execution (multi-file project)
<?php
$extra = 4;
$count = count([2, 3, $extra]);
$total = 2 + 3 + $extra;
$average = $total / $count;

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "total=" . $total . "\n";
echo "average=" . $average . "\n";

<?php
$extra = 1;
$count = count([2, 3, $extra]);
$total = 2 + 3 + $extra;
$average = $total / $count;

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "total=" . $total . "\n";
echo "average=" . $average . "\n";

<?php
$extra = 9;
$count = count([2, 3, $extra]);
$total = 2 + 3 + $extra;
$average = $total / $count;

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "total=" . $total . "\n";
echo "average=" . $average . "\n";

  1. $extra ← 4, $count ← 3, $total ← 9, $average ← 3

    1<?php2$extra→ 4 = 4; //@extra=1, 93$count→ 3 = count([2, 3, $extra4]);4$total→ 9 = 2 + 3 + $extra4;5$average→ 3 = $total9 / $count3;67echo "extra=" . $extra4 . "\n";8echo "count=" . $count3 . "\n";9echo "total=" . $total9 . "\n";10echo "average=" . $average3 . "\n";
    outputextra=4
count=3
total=9
average=3

  1. $extra ← 1, $count ← 3, $total ← 6, $average ← 2

    1<?php2$extra→ 1 = 1;3$count→ 3 = count([2, 3, $extra1]);4$total→ 6 = 2 + 3 + $extra1;5$average→ 2 = $total6 / $count3;67echo "extra=" . $extra1 . "\n";8echo "count=" . $count3 . "\n";9echo "total=" . $total6 . "\n";10echo "average=" . $average2 . "\n";
    outputextra=1
count=3
total=6
average=2

  1. $extra ← 9, $count ← 3, $total ← 14, $average ← 4.6666666666667

    1<?php2$extra→ 9 = 9;3$count→ 3 = count([2, 3, $extra9]);4$total→ 14 = 2 + 3 + $extra9;5$average→ 4.6666666666667 = $total14 / $count3;67echo "extra=" . $extra9 . "\n";8echo "count=" . $count3 . "\n";9echo "total=" . $total14 . "\n";10echo "average=" . $average4.6666666666667 . "\n";
    outputextra=9
count=3
total=14
average=4.6666666666667