JSON and Data Shapes

JSON Numbers

JSON numbers decode into numeric values that can be used in calculations.

numeric field After decoding, calculate with the selected numeric field and print scalar results.

JSON Numbers

qty
json_numbers.php
Replay: real traced execution (multi-file project)
<?php
$qty = 3;
$json = '{"item":"pen","qty":' . $qty . '}';
$count = json_decode($json, true)["qty"];
$total = $count * 2;

echo "qty=" . $qty . "\n";
echo "total=" . $total . "\n";

<?php
$qty = 1;
$json = '{"item":"pen","qty":' . $qty . '}';
$count = json_decode($json, true)["qty"];
$total = $count * 2;

echo "qty=" . $qty . "\n";
echo "total=" . $total . "\n";

<?php
$qty = 8;
$json = '{"item":"pen","qty":' . $qty . '}';
$count = json_decode($json, true)["qty"];
$total = $count * 2;

echo "qty=" . $qty . "\n";
echo "total=" . $total . "\n";

  1. $qty ← 3, $json ← {"item":"pen","qty":3}, $count ← 3, $total ← 6

    1<?php2$qty→ 3 = 3; //@qty=1, 83$json→ {"item":"pen","qty":3} = '{"item":"pen","qty":' . $qty3 . '}';4$count→ 3 = json_decode($json, true)["qty"]3;5$total→ 6 = $count3 * 2;67echo "qty=" . $qty3 . "\n";8echo "total=" . $total6 . "\n";
    outputqty=3
total=6

  1. $qty ← 1, $json ← {"item":"pen","qty":1}, $count ← 1, $total ← 2

    1<?php2$qty→ 1 = 1;3$json→ {"item":"pen","qty":1} = '{"item":"pen","qty":' . $qty1 . '}';4$count→ 1 = json_decode($json, true)["qty"]1;5$total→ 2 = $count1 * 2;67echo "qty=" . $qty1 . "\n";8echo "total=" . $total2 . "\n";
    outputqty=1
total=2

  1. $qty ← 8, $json ← {"item":"pen","qty":8}, $count ← 8, $total ← 16

    1<?php2$qty→ 8 = 8;3$json→ {"item":"pen","qty":8} = '{"item":"pen","qty":' . $qty8 . '}';4$count→ 8 = json_decode($json, true)["qty"]8;5$total→ 16 = $count8 * 2;67echo "qty=" . $qty8 . "\n";8echo "total=" . $total16 . "\n";
    outputqty=8
total=16