PHP supports eight primitive types.
Four scalar types:
The type of a variable is usually not set by the
programmer; rather, it is decided at runtime by PHP
depending on the context in which that variable is
used.
注: If you want to check out the type and value of a certain expression, use var_dump().
注: If you simply want a human-readable representation of the type for debugging, use gettype(). To check for a certain type, do not use gettype(), but use the is_type functions. Some examples:
?php $bool = TRUE; // a boolean $str = "foo"; // a string $int = 12; // an integer echo gettype($bool); // prints out "boolean" echo gettype($str); // prints out "string" // If this is an integer, increment it by four if (is_int($int)) { $int += 4; } // If $bool is a string, print it out // (does not print out anything) if (is_string($bool)) { echo "String: $bool"; } ?
If you would like to force a variable to be converted
to a certain type, you may either
cast the variable or use the
settype() function on it.
Note that a variable may be evaluated with different
values in certain situations, depending on what type it is
at the time. For more information, see the section on Type
Juggling.