1. Regarding case
PHP’s built-in functions and structures are not case-sensitive.
For example:
Copy code The code is as follows:
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:
function Test()
{
echo("Hello PHP");
}
Test();
TEST();
test();
?>
> ;
But variables are case-sensitive.
2. Variables
I just want to mention one thing here. Anyone who has even a little contact with PHP will know that variables declared in PHP start with a dollar sign ($).
In the previous example, we can also see this.
3. Type judgment function
In PHP, there are eight data types: integer, floating point, string, Boolean, array, object, NULL and resource type.
There is a very important function when judging the type, the format is is_XX.
For example:
Copy code The code is as follows:
$intTest=1;
echo(is_int($intTest));
echo("
");
$stringTest="Test";
echo(is_string($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.
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