#php webdevelopment

The main way to store information in the middle of a PHP program is by using a variable.

Here are the most important things to know about variables in PHP.

· All variables in PHP are denoted with a leading dollar sign ($).

· The value of a variable is the value of its most recent assignment.

· Variables are assigned with the = operator, with the variable on the left-hand side and the expression to be evaluated on the right.

· Variables can, but do not need, to be declared before assignment.

· Variables in PHP do not have intrinsic types - a variable does not know in advance whether it will be used to store a number or a string of characters.

· Variables used before they are assigned have default values.

· PHP does a good job of automatically converting types from one to another when necessary.

· PHP variables are Perl-like.

PHP has a total of eight data types which we use to construct our variables −

· Integers − are whole numbers, without a decimal point, like 4195.

· Doubles − are floating-point numbers, like 3.14159 or 49.1.

· Booleans − have only two possible values either true or false.

· NULL − is a special type that only has one value: NULL.

· Strings − are sequences of characters, like 'PHP supports string operations.'

· Arrays − are named and indexed collections of other values.

· Objects − are instances of programmer-defined classes, which can package up both other kinds of values and functions that are specific to the class.