Learn PHP Learn PHP2 step by step - PHP type

1. Regarding case
PHP’s built-in functions and structures are not case-sensitive.
For example:

Copy code The code is as follows:

< ?php
echo("Hello PHP");
ECHO("Hello PHP");
Echo("Hello PHP");
?>

These three The effect is the same.
Others, user-defined class names and method names are also case-insensitive.
For example:

Copy the code The code is as follows:

< ?php
function Test()
{
echo("Hello PHP");
}
Test();
TEST();
test();
?>

But variables are case-sensitive.
");
$stringTest="Test";
echo(is_string($stringTest));
echo("
");
echo(is_int($stringTest));
?>

The above introduces the step-by-step learning of PHP2 - PHP type, including the content of learning PHP. I hope it will be helpful to friends who are interested in PHP tutorials.