PHP

Variables

Every PHP variable name starts with $: $name = "Ada";. Like Python or JavaScript, you don't declare a type, it's inferred from whatever value you assign.

Example: variables inside a string

<?php
  $name = "Ada";
  $age = 21;
  echo "$name is $age years old.";
?>

Ada is 21 years old.

Variables placed directly inside a double-quoted string ("$name") are automatically substituted with their value, this only works inside double quotes; single-quoted strings ('$name') print the literal text $name instead, with no substitution at all. That distinction catches a lot of beginners the first time they switch quote styles without thinking about it.

<?php
  $name = "Ada";
  $age = 21;
  echo "$name is $age years old.";
?>

Ada is 21 years old.

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