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Chapter 6. Types
Table
of Contents
Introduction
Booleans
Integers
Floating point numbers
Strings
Arrays
Objects
Resource
NULL
Pseudo-types used in this documentation
Type Juggling
Introduction
PHP supports eight primitive types.
Four scalar types:
Two compound types:
And finally two special types:
This manual also introduces some pseudo-types for readability
reasons:
You may also find some references to the type "double". Consider
double the same as float, the two names exist only for historic
reasons.
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.
Note: If you want to check out the type and
value of a certain expression, use var_dump().
Note: 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:
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. Also, you may be interested in viewing the type
comparison tables, as they show examples of various type related
comparisons.
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